Science Highlights
September 21st, 2017
Extreme conditions research cannot be accomplished without state-of-the-art instruments. Thus, tools must be improved in order to access new domains and to expand the range of properties measured. In high pressure neutron diffraction, for example, one limitation that sample sizes need to be much larger than is the case for x-ray diffraction. This...
September 21st, 2017
The properties of hydrogen at extreme pressures and temperatures are of great interest to condensed matter physics, astrophysics, and planetary science due to the element’s putative simplicity and abundance in the visible universe. Of particular interest is the desire to know pressure-temperature conditions over which hydrogen is converted from...
September 12th, 2017
Extending his original predictions for metallic hydrogen, Cornell's Neil Ashcroft later proposed that hydrogen-rich materials containing main group elements might exhibit superconductivity at accessible pressures. The hydrogen in these structures, he argued, may be considered “chemically precompressed.” These proposals, which were based on the...
June 14th, 2017
Recent developments at HPCAT have resulted in a number of important new experimental techniques that take advantage the properties of white beam radiation for the analysis of materials at high pressure. One such key capability is white beam radiography combined with energy-dispersive x-ray diffraction to give structural information with increasing...
May 9th, 2017
The annual Stewardship Science Academic Programs (SSAP) Symposium was held in Naperville, IL on April 12-13, 2017. CDAC Director Russell Hemley gave an overview of the Center and its accomplishments in the scientific...
May 5th, 2017
It is difficult to overestimate the importance of silicon when it comes to computing, solar energy, and other technological applications - not to mention the fact that it is the second-most abundant element in Earth’s crust, in terms of mass percent. The most common form of silicon crystallizes in the same structure as diamond (Si-I), but other...
February 21st, 2017
Cementite is the most common carbide compound in steels and has also been proposed as a host for the light element in Earth’s core. Because the material is metastable at ambient pressure and temperature, its synthesis is challenging, and high pressure techniques are required. As a result, key thermodynamic properties, particularly the temperature-...
February 16th, 2017
A new paper reports the discovery and characterization of a new iron-rich high-pressure mineral named for CDAC Director Russell J. Hemley in recognition of his distinguished contributions to high-pressure research and mineral physics. The new mineral is the iron-rich analogue of akimotoite, a mineral with MgSiO3 composition and...
February 14th, 2017
In a recent article in The Washington Post, CDAC Director Russell Hemley weighs in on the extraordinary properties of diamond that make it so important in new scientific and technological applications. “Forget the ring: Lab-grown diamond’s are a scientist’s best friend,” published on the front page of the Post’s February 14th...
December 5th, 2016
BaReH9 is the most hydrogen-rich inorganic salt discovered thus far, and is of great interest in the study of superconductivity in dense hydrides and also the metallization of hydrogen at high pressure. The unusual composition of this material suggests that investigation of its high pressure properties should offer a number of important insights...
December 1st, 2016
Boron Carbide exhibits a number of important material properties, among them extreme hardness approaching that of diamond, and a very high melting point. However, it is the low density of the material that makes it attractive for applications requiring high mechanical strength and light weight. Its properties are due to the unique crystal...
November 29th, 2016
A recent advance toward the goal of increasing achievable static pressures beyond the mechanical limits imposed by the diamond anvil cell has been in the development of “two-stage” diamond anvils. Two-stage anvils consist of a small “micro-anvil” with a culet size on the order of 30 microns fixed onto the culet of a larger diamond anvil with a...
November 28th, 2016
Chemical reactions involving acetonitrile most often occur as the result of activating the C-N triple bond, while the C-H bonds are generally considered inert. Weak intermolecular hydrogen bonds of the N - - H - C type, however are susceptible to modification by applied pressure. Now a group including CDAC Research Scientist Zhenxian Liu, have...
November 10th, 2016
Understanding the behavior of dense hydrogen remains a major challenge in both condensed matter physics and energy science, and high-pressure experiments and theoretical calculations have uncovered a number of novel phenomena in this fundamental system. Theoretical work by CDAC Research Scientist Ivan Naumov and CDAC Director Russell J. Hemley...
November 1st, 2016
It has long been recognized that applied pressure can significantly change the conventional patterns of chemical reactivity predicted by the structure of the Periodic Table. At the same time, among thousands of known interactions between elements in the Periodic Table, there remain chemical bonds that are curiously absent. But is high pressure...
October 26th, 2016
Understanding and characterizing structural and bonding properties of the carbon-hydrogen (C-H) system over a broad range of conditions is crucial for developing new high-strength materials for energy applications. In addition, examination of the C-H system in extreme environments also plays an important role in the search for new materials with...
October 25th, 2016
Creating new materials that efficiently store and release hydrogen is essential for further developing hydrogen-based energy technologies. Over the last several years, high-pressure studies have shown that materials based on water ice could perform this store-and-release function. Now, new results from a group including researchers from Carnegie...
October 1st, 2016
Using computational theory as well as x-ray and neutron scattering scattering measurements, the CDAC group at Caltech has shown that the alloy FeTi undergoes an unusual change in phonon dynamics associated with changes in its electronic properties at high temperatures. This research effort included current CDAC student Fred Yang and CDAC Academic...
September 6th, 2016
Materials combining the hardness and strength of diamond with the higher thermal stability of cubic boron nitride (cBN) have broad potential value in science and engineering. Reacting nanodiamond with cBN at high pressures and high temperatures provides a pathway to such materials. CDAC partner Steve Jacobsen (Northwestern), along with scientists...
July 5th, 2016
Depleted uranium and its alloys are important engineering materials due to their high density. It is well known that depleted uranium can be alloyed to improve several elastic and plastic related properties, to enhance corrosion resistance, and to allow flexible heat treatability. In recent experiments performed at HPCAT, CDAC Steering Committee...
July 5th, 2016
Hydrogen is the most abundant element in the cosmos. It’s also the simplest, with only a single electron in each atom, and forms a transparent gas under ordinary conditions. But that simplicity is deceptive, for example, at the extreme pressures and temperatures found inside of giant planets. New work published in Physical Review Letters shows...
July 1st, 2016
Applied pressure is a powerful tool for studying rare earth systems with intermediate valence because their electronic states are sensitive to small changes in interatomic separation. Recent experiments at HPCAT using resonant x-ray emission spectroscopy have explored the pressure dependence of the f-electron occupancy in the Kondo insulator SmB6...
July 1st, 2016
Hydrogen bonds are widely present in many substances and are responsible for defining the three-dimensional structures of proteins, the unusual physical properties of water and ice, and are found in many geologically significant minerals. The balance between hydrogen bonds and other kinds of interatomic forces can have significant effects on a...
May 13th, 2016
The sodium counterpart to LiFePO4 has recently attracted attention as a potentially promising cathode material. Sodium is one of the major rock-forming elements in the Earth’s crust and is both environmentally abundant and affordable. As a result, the development of sodium analogues to lithium cathode materials is appealing, especially for large...
March 10th, 2016
A new technology platform to study high-speed impacts on a tabletop has been developed at the University of Illinois. This method uses a laser to launch thin metal foils at km/s velocities. Although “laser-launched flyer plates” have been studied for more than 30 years, they have not been broadly utilized in shock compression science partly due to...
March 4th, 2016
The annual Stewardship Science Academic Programs (SSAP) Symposium was held in North Bethesda, MD on February 17-18, 2016. CDAC Director Russell Hemley gave an overview of the Center and its accomplishments in the scientific program, education and outreach, and technical developments during the past year.
March 3rd, 2016
Ferroelectric materials (switchable spontaneous electric polarization under an external electric-field) are also piezoelectric (convert mechanical energy into electric energy) and pyroelectric (convert a temperature change into electric energy). The combined properties of memory, piezoelectricity, and pyroelectricity, make ferroelectric materials...
March 3rd, 2016
A new class of high Tc superconductors having a dense carbon framework structures is predicted using first-principles calculations. The current search for high-temperature superconductivity is now focused on materials containing low-Z elements due to the large phonon contribution necessary for BCS-type behavior. An additional strategy for...
December 11th, 2015
On December 8-9, an NNSA review of the Carnegie-DOE Alliance Center was held at the Advanced Photon Source, Argonne National Laboratory. Nine CDAC partners, two NNSA Laboratory partners, and 20 students participated in the event. CDAC partners gave overviews of their research programs, while the NNSA Laboratory partners provided updates on the...
November 12th, 2015
Producing materials by chemical vapor deposition (CVD) has become an important means of synthesis, in which high-energy molecular and atomic species generate a kinetically stable phase trapped in local energy minimum. Single crystal, polycrystalline, and nanocrystalline diamond now can be produced by microwave plasma assisted CVD (MPCVD).
August 14th, 2015
A collection of 10 papers was published in a single volume of the Review of Scientific Instruments. These papers represent a snapshot of recent developments at HPCAT in advancing high pressure synchrotron techniques. The following articles were published as "Special Topic: X-ray Techniques at the HPCAT Advanced Photon Source."
July 10th, 2015
The iron-oxygen system is the most important reference of a rock’s oxidation state. Even as minor components in many petrologic systems, iron oxides can play a critical role in controlling redox equilibria, which in turn affect the speciation of fluid phases, chemical differentiation, melting behavior, and other important physical properties....
July 9th, 2015
CDAC graduate student Greg Hohensee and his research advisor, CDAC Academic Partner David Cahill at the University of Illinois, have used diamond anvil cell techniques to uncover new physics associated with heat transfer across diamond-metal interfaces. Their paper, published in Nature Communications, illustrated the critical role of pressure as...
July 2nd, 2015
The matter that makes up distant planets and even-more-distant stars exists under extreme pressure and temperature conditions, and includes the noble gases, some of which - such as helium and neon - are household names. New work by a group from Carnegie, the University of Edinburgh, DESY, and Howard University used laboratory techniques to...
June 22nd, 2015
A team of scientists from Carnegie and George Mason University, using facilities at HPCAT, have provided new insights on the behavior of silica under pressure at room temperature. Silica is one of the most abundant minerals and a major component of the Earth’s crust and mantle. Its various high-pressure forms make it an important study subject in...
May 28th, 2015
The Atomic Heritage Foundation hosted series of events on June 2-3, 2015 to commemorate the 70th Anniversary of Manhattan Project. The program was held at the headquarters of the Carnegie Institution of Washington. A reunion and reception for Manhattan Project veterans and their families was held on Tuesday, June 2, beginning at 2:30 PM. This was...
May 27th, 2015
A recent systematic search for stable calcium carbides carried out using an evolutionary structure searching algorithm resulted in the prediction of six stable phases from ambient pressure up to 100 GPa. Among the rich and diverse chemistry predicted in these various phases, a particularly remarkable feature was found in the 2D metallic phase of...
April 23rd, 2015
New work from Carnegie scientists Russell Hemley and Ivan Naumov hones in on the physics underlying the recently discovered fact that some metals stop being metallic under pressure. Metals are compounds that are capable of conducting the flow of electrons that make up an electric current. Other materials, called insulators, are not capable of...
March 18th, 2015
The annual Stewardship Science Academic Programs (SSAP) Symposium was held in Santa Fe, NM on March 11-12, 2015. At the poster session, 18 CDAC graduate students presented their work and Eloisa Zepeda-Alarcon received a Best Poster Award for her presentation. CDAC Coordinator Stephen Gramsch gave an overview of the Center and its accomplishments...
February 27th, 2015
As iron is heated, the arrangement of the atoms in the solid changes several times before the iron finally melts. This unusual behavior is one reason why steel is so strong. The atomic-level details of how and why iron takes on so many different forms during heating remains a mystery, however. Recent work by Caltech CDAC scientists provides...
February 11th, 2015
Only a small fraction of our planet’s total carbon budget is found at the surface. In fact, Earth’s mantle is thought to be the largest carbon reservoir. Carbonates, and in particular ferromagnesite ((Mg,Fe)CO3), are likely candidates for deep-Earth carbon storage and therefore play a key role in the deep carbon cycle. The behavior of these...
February 10th, 2015
Carbon exists in a variety of structural motifs as a result of its ability to adopt sp-, sp2-, and sp3-type bonding modes. Graphite, diamond, and lonsdaleite (hexagonal diamond) are well-established allotropic forms of carbon, but in recent years fullerenes, nanotubes, graphene and even amorphous carbon have received a increasing attention as a...
January 8th, 2015
CDAC is pleased to announce the release of our Annual Report for 2013-2014.
December 18th, 2014
In a paper recently released in Physical Review Letters, a group including CDAC graduate student Dane Tomasino, CDAC Partner Choong-shik Yoo (both from Washington State University), and Jesse Smith from HPCAT, report the significant discovery of a novel layered, singly-bonded polymeric form of nitrogen (LP-N). The...
December 18th, 2014
The melting line of cerium metal is characterized by an unusual broad minimum at approximately 3.3 GPa. More recent work has extended the established pressure range of the melt line to nearly 30 GPa, where the melting temperature has risen to 1370 K from its minimum at 935 K. This behavior of the melting line suggests that two different liquid...
December 12th, 2014
Seismic shear waves passing through the Earth’s core travel at about half the speed of iron and related alloys at similar pressures, consistent with a “density deficit” in the core relative to iron or iron-nickel alloys. It is now widely accepted that, in addition to an iron-nickel alloy, Earth's inner core contains one or more lighter elements....
December 9th, 2014
New work from Carnegie's Ivan Naumov and Russell Hemley delves into the chemistry underlying some surprising recent observations about hydrogen and reveals remarkable parallels between hydrogen and graphene under extreme pressure. Their work is the cover story in the December issue of Accounts of Chemical Research. Hydrogen is the...
August 21st, 2014
CDAC Research Scientist Maddury Somayazulu visited Torredu, India in September and gave a talk to the children of the village about how science impacts society. Torredu is a village some 60 kilometers from Kakinada. The school itself is a success story in that this village of 5,000 started this government school on a piece of land donated by a...
August 1st, 2014
Increased study of the nature of planetary interiors, as well as the current effort to produce inertial confinement fusion, both call for an understanding of matter at ultra-dense states, characterized by pressures in the terapascal range (TPa, tens of millions of atmospheres). The possible existence of carbon-rich planets has created interest in...
July 29th, 2014
The study of the behavior of polymorphic organic solids at high pressure is a relatively new and rapidly growing area of interest. The applications span a wide ranging field which includes the pharmaceutical industry, where often times different crystal phases of the same drug can have different physiological effects. CDAC Graduate Student Spencer...
July 28th, 2014
The high water storage capacity of minerals in Earth’s mantle transition zone (410- to 660-kilometer depth) implies the possibility of a deep H2O reservoir, which could cause dehydration melting of vertically flowing mantle. In recent work, CDAC scientists and colleagues from the University of New Mexico, University of Southern California, and...
June 27th, 2014
Understanding the basic chemical interactions in clathrate compounds is important in areas as diverse as energy storage and pharmaceutical development. At Carnegie, Timothy Strobel and CDAC intern Viktor Rozsa (Hillsdale College, now at University of Chicago) have recently discovered extremely novel behavior in hydrogen-loaded hydroquinone (β-HQ-...
May 15th, 2014
The Frontier Synchrotron Infrared Spectroscopy (FIS) Beamline under Extreme Conditions has been approved as one of the eight NxtGen beamlines to be developed and constructed at NSLS-II. FIS is the successor of the IR-DAC facility (U2A) at NSLS, the highly productive, Carnegie-managed user facility supported by COMPRES and CDAC, and the only...
May 15th, 2014
In any material, the increase in density with decreasing volume is directly related to the nature of the interatomic interactions. For typical crystalline materials, the volume varies as the cube of the change in interatomic distance. In amorphous materials, however, an irregular network of interatomic interactions can lead to deviations from...
May 15th, 2014
Multilayered transition metal dichalcogenides (TMDs), such as molybdenum disulfide, fall within a class of 2D materials that may exhibit remarkable optical, electronic, and structural properties depending on the interactions both within and between atomic layers. A number of “impurity” methods—doping, intercalation, and site defects, for example—...
March 28th, 2014
Studies of molecular hydrogen at static or sustained multimegabar pressures are difficult as a result of challenges in containing the samples under these conditions, and making accurate measurements of the material sample in the diamond anvil cell. Nevertheless, recent advances in diamond anvil cell techniques have now enabled measurements on...
February 27th, 2014
The annual Stewardship Science Academic Programs (SSAP) Symposium took place in North Bethesda, ND from February 19-20, 2014. Individual grant recipients and center directors from the four divisions of the program (High Energy Density Physics, Low Energy Nuclear Science, Materials Properties Under Extreme Conditions, and National Laser User...
February 4th, 2014
New research shows that a remarkable defect in synthetic diamond produced by chemical vapor deposition allows researchers to measure, witness, and potentially manipulate electrons in a manner that could lead to new “quantum technology” for information processing. Normal computers process bits, the fundamental ones and zeros, one at a time. But in...
December 23rd, 2013
Table salt, sodium chloride, is one of the first chemical compounds that schoolchildren learn. Standard chemistry textbooks say that sodium and chlorine have very different electronegativities and thus must form an ionic compound with a well-defined composition. Sodium’s charge is +1, chlorine’s charge is -1; sodium will give away an electron,...
December 23rd, 2013
The behavior of the Group 4 metals titanium, zirconium, and hafnium at extreme conditions has received a great deal of attention, particularly due to the importance of Ti as a light structural metal, and Zr and Hf as components of nuclear reactors. At ambient conditions, these metals crystallize in a distorted hexagonal close-packed structure (α)...
December 23rd, 2013
Galfenol is a new class of iron-based, magnetic Fe1-xGax alloy that exhibits giant magnetostriction. It has attracted considerable attention because of its potential for use in mechanical devices where resistance to fracture is an important criterion. Maximum values of the magnetostriction coefficient (3/2λ100) of 400 ppm have been observed in...
December 23rd, 2013
Hydrocarbons from the Earth make up the oil and gas that heat our homes and fuel our cars. The study of the various phases of molecules formed from carbon and hydrogen under high pressures and temperatures, like those found in the Earth's interior, helps scientists understand the chemical processes occurring deep within planets, including Earth....
December 23rd, 2013
The key to understanding Earth’s evolution is to look at how heat is conducted in the deep lower mantle—a region some 400 to 1,800 miles (660 to 2,900 kilometers) below the surface. A research group including former CDAC post-doctoral associate Allen Dalton (now at Defense Threat Reduction Agency), Carnegie-CDAC Scientist Alexander Goncharov, CDAC...
July 30th, 2013
Hydrogen is deceptively simple. It has only a single electron per atom, but it powers the sun and forms the majority of the observed universe. As such, it is naturally exposed to the entire range of pressures and temperatures available in the whole cosmos. New theoretical work at the Geophysical Laboratory provides surprising insight into the...
July 3rd, 2013
The annual SSAA Program Symposium took place in Albuquerque, NM from June 27-28, 2013. Individual grant recipients and center directors from the three divisions of the program (High Energy Density Physics, Low Energy Nuclear Science, and Materials Properties Under Extreme Conditions) gave updates on center or group activities and progress.
July 2nd, 2013
CDAC was featured prominently in the 2013 Stockpile Stewardship Academic Programs Annual Report, which was released just prior to the recent SSAP Annual Review Symposium. The cover of the report featured an image of diffuse x-ray scattering from Pb(Sc,Nb)O3 obtained by Carnegie-CDAC Research Scientist Muhetaer Ahart. The diffuse scattering, which...
June 4th, 2013
The CDAC-supported Paris-Edinburgh Cell Workshop 2013 was held on May 23-24 at the Advanced Photon Source and HPCAT 16BM-B, Argonne National Laboratory. More than 45 participants attended the two-day workshop. The workshop was composed of four technical training courses, as well as a discussion forum related to current Paris-Edinburgh cell...
June 3rd, 2013
New work from a team of Carnegie scientists including Chang-sheng Zha, Zhenxian Liu, Muhtar Ahart, Reinhard Boehler, and Russell Hemley using intense infrared radiation shines new light on the fundamental material hydrogen at extreme pressures and reveals the details of a surprising new form of the solid under these conditions.
April 24th, 2013
The study of matter at extreme conditions represents a forefront area of research activity across the sciences, including physics, chemistry, materials science and even biology. Advancing the frontier of extreme conditions science requires powerful micro- sampling probes to access minute samples through the vessel walls and to separate weak sample...
April 24th, 2013
A team led by Wenge Yang (HPSynC) and including researchers from Carnegie, the Advanced Photon Source, and University College London has made a major breakthrough in measuring the structure of nanomaterials under pressures. For the first time, a way to get around the severe distortions of high-energy X-ray beams that are used to image...
April 19th, 2013
The (Mg,Fe)SiO3 crystallizes into a postperovskite (pPv) phase in polycrystalline form at high pressure-temperature conditions and becomes amorphous upon release of pressure. Structural refinement of the pPv phase at extreme conditions is challenging because of uncertainties in diffraction intensity caused by texturing of the sample and spotty...
April 19th, 2013
Understanding polymorphism in liquids provides key insights into the complex nature of the liquid state, and may now be studied in detail as a result of advances in synchrotron x-ray diffraction techniques. The observation of a liquid-liquid transition in a material having two distinct liquid phases of differing density is experimentally...
March 22nd, 2013
CDAC Partner Jung-Fu Lin and colleagues from The University of Texas at Austin and Amherst College have described a new technique that might one day reveal the composition and characteristics of the deep Earth in higher detail than ever before. However, the technique relies on the long-range electron spin-spin interaction, a fifth force of nature...
December 21st, 2012
Phase transformations are a fundamental aspect of high pressure research, but the atomic level details of such transformations are difficult to observe experimentally. How is it that one solid phase transforms to another under increasing pressure? From the point of view of thermodynamics, the free energy of one phase becomes lower than the other...
December 20th, 2012
Understanding f-electron elements has been an important problem in condensed matter physics for many decades. The challenges have involved developing a first-principles theoretical framework due to the fact that f electrons can exhibit either localized, highly correlated or itinerant behavior. In addition, f-elements are characterized by multiple...
December 17th, 2012
When a material is subject to external stresses, it will eventually change its shape. Initially, such changes are elastic and reverse when the stress is relieved. When the intrinsic strength of the material is exceeded, however, the changes become permanent and can result in breaking or shattering, but permanent changes in shape are also possible.
November 20th, 2012
The mantles of Earth and other rocky planets are rich in magnesium and oxygen. Due to its simplicity, the mineral magnesium oxide is a good model for studying the nature of planetary interiors. Carnegie's Stewart McWilliams and colleagues from Lawrence Livermore National Laboratory and the University of California – Berkeley, including CDAC...
November 5th, 2012
A new efficient way to pump heat using crystals has been discovered by Carnegie Summer Scholar Maimon Rose (University of Chicago) and Carnegie Staff Scientist Ronald E. Cohen. The crystals can pump or extract heat, even on the nanoscale, so they could be used on computer chips to prevent overheating or even meltdown, which is currently a major...
November 1st, 2012
HPCAT celebrated its 10th anniversary by hosting a workshop on Advances in Matter under Extreme Conditons at the Advanced Photon Source from October 10-12, 2012. Over 100 people attended from the US and abroad. A report will be forthcoming consisting of two major parts, with Part I covering the advances in high pressure synchrotron techniques and...
September 6th, 2012
FeO is a fundamentally important material as a member of the transition metal monoxides, which are important for understanding electronic properties such as insulator-metal transitions in condensed matter. Magnesiowustite (Mg,Fe)O, also known as ferropericlase, is one of the key minerals that make up the Earth's lower mantle. The stoichiometric...
August 23rd, 2012
Under normal conditions, pure carbon exhibits vastly different physical properties depending on its structure. For example, graphite is soft, but diamond is one of the hardest materials known. Graphite conducts electricity, but diamond is an insulator. Graphite is the thermodynamically stable phase of carbon at ambient contitions, and the...
August 22nd, 2012
For decades, physicists have predicted that the nickel oxide would transition from an insulator to a metal under compression, but their predictions had not been confirmed until now. Carnegie scientist Viktor Struzhkin and colleagues from the Russian Academy of Sciences have discovered the conditions under which nickel oxide can turn into an...
August 22nd, 2012
Magnetic elements such as iron typically do not superconduct, and their magnetic nature has been considered incompatible with superconductivity. With the discovery in 2008 of the iron pnictide superconductors, however, a new set of problems concerned with the nature of the superconducting state has been under intense investigation. In particular...
August 20th, 2012
Information on the behavior of polymers at high pressure cannot be obtained using conventional x-ray diffraction techniques, due to the lack of long-range order in the material. Such information, however, is becoming increasingly important due to the key role of polymeric materials in a number of modern technologies. An example is the behavior of...
August 17th, 2012
A team of CDAC scientist led by Lin Wang (HPSynC) and including Wenge Yang (HPSynC), Zhenxian Liu (U2A), Stanislav Sinogeikin (HPCAT), Yue Meng (HPCAT), and CDAC partner Wendy Mao (Stanford), along with collaborators from Jilin University, the University of Nebraska, and Argonne National Laboratory, has observed a new form of very hard carbon...
June 20th, 2012
The conduction of heat in materials at extreme conditions is important in many processes, including the dynamics of deep planetary interiors, fast chemical reactions and explosions. Diamond anvil cells (DACs) are used routinely to produce extreme pressures in materials, and with pulsed laser heating, extreme temperatures are also accessible. Under...
June 15th, 2012
Earth’s inner core is by far the most remote region of the planet and exists at conditions of over 3.6 million atmospheres (360 GPa) pressure and temperatures perhaps in the 6000 K range. While remote, its existence affects the geodynamo and how the Earth’s interior has evolved through time. A number of enigmatic properties of the Earth’s inner...
May 31st, 2012
Quantum criticality, a phenomenon that is particularly relevant in strongly electron-correlated systems, refers to phase transitions that take place at absolute zero and are driven by zero-point quantum fluctuations. Over the past several decades, the experimental and theoretical study of quantum critical points has revealed intriguing new...
May 25th, 2012
Carnegie scientists and their collaborators have discovered new properties in the magnetic material Ge2Sb2Te5 (GST) under pressure. Understanding and exploiting these unusual properties may eventually lead to new types of memory drives and computer systems that store data more quickly, last longer and allow far more capacity than current data...
May 23rd, 2012
Dense transition metal borides are a new class of the growing family of superhard materials. These compounds may find use as cutting tools and protective coatings. In the study published in Physical Review B, CDAC Partner Abby Kavner, CDAC student Matt Armentrout, and collaborators from UCLA examined the high pressure behavior of a new superhard...
April 3rd, 2012
Even though hydrogen is the most abundant element in the universe, an understanding of its properties under extreme pressure and temperature conditions is not yet complete. Ultimately, the fundamental physics behind the behavior of this seemingly simple element can inform and expand our understanding of matter as a whole. New work from Carnegie...
February 28th, 2012
New Laser Interferometry Technique Developed at LANL Print E-mail A new laser interferometry technique has been developed at Los Alamos National Laboratory (LANL). The project is led by Michael Furlanetto, a former Carnegie Postdoctoral Fellow. Michael received his Ph.D. in physical chemistry at the University of California - Berkeley and carried...
February 23rd, 2012
The annual SSAA Program Symposium took place in Washington, DC from February 22-23 and drew participants from around the country. Individual grant recipients and center directors from the three divisions of the program (High Energy Density Physics, Low Energy Nuclear Science, and Materials Properties Under Extreme Conditions) gave updates on...
February 23rd, 2012
New experiments set the record of the superconducting transition temperatures for a new family of iron-based selenide superconductors. These materials were recently found to superconduct below 30 Kelvin, but their transition temperatures decline until approaching absolute zero temperature with the application of pressure. Now Carnegie scientists...
January 12th, 2012
Multicarat colorless single-crystal diamond has been produced using chemical vapor deposition techniques by researchers from Carnegie. The paper is featured on the frontispiece of a recent issue of Physica Status Solidi (a). Diamond is a unique material with multiple superlative properties. For example, diamond is the ultimate material for many...
November 4th, 2011
The Year 9 CDAC Review took place on October 25 at the Advanced Photon Source, Argonne National Laboratory. Overview talks were given by Carnegie's Russell Hemley, Stephen Gramsch, Ho-kwang Mao, Guoyin Shen, and Wenge Yang. CDAC Academic Partners Steven Jacobsen (Northwestern University), Dana Dlott (University of Illinois), Yogesh Vohra (...
September 20th, 2011
Researchers at Caltech, Oak Ridge National Laboratory, the Air Force Research Laboratory, and Carnegie observed for the first time how vibrations of atoms in a crystal lattice (phonons) can stabilize an ordered phase more than a disordered phase. This is the reverse of what has been exclusively observed until now; usually the stronger chemical...
September 19th, 2011
Carbon has long been a rich and active research area offering exciting discoveries of new allotropes including both crystalline and disordered structures such as buckyballs, carbon nanotubes, graphene and diamond-like amorphous carbon with numerous and exciting potential in technological applications.
September 13th, 2011
Aluminum is one of the common materials which we use daily and holds faced-center-cubic structure at ambient environment. Theoretical calculation has predicted the possible phase transition of fcc to hcp, and hcp to bcc under high pressures at 120 GPa and over 380 GPa, respectively, but so far only the first transition has been observed...
September 8th, 2011
CDAC and HPCAT continue to participate in discussions focusing on the continued development of the Matter-Radiation Interactions in Extremes (MaRIE) facility, which will be located at the Los Alamos National Laboratory. By providing beam time and technical expertise for feasibility experiments, CDAC and HPCAT are also taking an active role in the...
August 3rd, 2011
CDAC scientists recently participated in a workshop entitled "Basic Research Directions for User Science at the National Ignition Faclilty (NIF)," from May 10-12 in Arlington, Virginia. The purpose of the workshop was to explore new scientific opportunities that will be possible with NIF, the world's largest and most powerful laser, which is...
August 2nd, 2011
Understanding the atomic arrangement in liquids is a key problem in the study of melt behavior at high pressure and temperature, both for metals and simple molecular systems, as well as more complex materials such as silicates. Compared to crystalline materials, liquids lack long-range translational periodicity and therefore have a much lower...
July 26th, 2011
Understanding the nature of chemical bonding in C-based materials at high pressure is receiving increasing attention as a result of the discovery of novel structures such as carbon nanotubes and graphene. X-ray inelastic scattering spectroscopy, also known as x-ray Raman spectroscopy (XRS), has emerged as a key technique for probing the interplay...
June 16th, 2011
New research by HPSynC’s Qiaoshi Zeng and scientists from Carnegie, George Mason University, Zhejiang University, and Stanford University, reveals the possibility of creating a metallic glass that is organized on a larger scale. They have discovered glasses that demonstrate order among the nearest neighboring atoms, called short-range order, and a...
April 29th, 2011
Elemental Ge is fundamental in condensed matter physics. Like the lighter elements in its family in the Periodic Table, C and Si, Ge crystal structure changes in Ge from the semiconducting diamond-type structure to metallic phases with increasing coordination. As such, accurate determination of the structures and transition pressures is an...
April 25th, 2011
Novel behavior of element one, hydrogen, induced by high P-T conditions has been observed at Carnegie by in situ Raman spectroscopy. The team studied the behavior of the symmetric stretching vibrational mode (molecular vibron) of hydrogen up to ~140 GPa and more than 1500 K and found unexpectedly large discontinuous softening of the vibron band...
April 19th, 2011
SiO2 glass is a prototypical network forming glass with a high degree of intermediate range order (IRO). The open structure of SiO2 glass makes it highly compressible, with molar volumes decreasing sharply with pressure exceeding those of crystalline polymorphs of quartz and coesite at around 20 GPa and approaching to that of dense stishovite at...
April 1st, 2011
For the fourth year in a row, the annual SSAA Program Symposium was hosted by the Carnegie Institution of Washington at its historic administration building in downtown Washington, DC. The meeting was held from February 15-17 and drew participants from around the country. Individual grant recipients and center directors from the three divisions of...
March 1st, 2011
Research carried out at Carnegie details the rich physics associated with how oxide materials transform from insulators to metals by application of pressure. The researchers from Stanford and the Geophysical Laboratory provide the first experimental evidence for LaMnO3 becoming metallic when the Jahn Teller distortion is suppressed.
February 18th, 2011
Following the success of the first two synchrotron measurements of dynamic compression carried out at the National Synchrotron Light Source (Beamline U2A) and the Advanced Photon Source (HPCAT beamline), there is now a need to consider the future of extreme conditions research using synchrotron radiation and plan for a path forward. Taking...
January 4th, 2011
Pacifichem 2010, the first international chemistry conference to feature a high-pressure symposium, took place in Honolulu, HI December 15-20, 2010. It was organized by the International Chemical Congress of Pacific Basin Societies and sponsored principally by CDAC and Lawrence Livermore National Laboratory.
December 21st, 2010
On Friday, December 17th, a workshop entitled "Exploring Giant Planets on NIF: A New Generation of Condensed Matter Science" was held at Livermore National Laboratory. Attended by scientists from around the country and hosted by CDAC Academic Partner Raymond Jeanloz and Steering Committee member G. W. (Rip) Collins, the workshop was convened to...
December 21st, 2010
A combined team from UC Berkeley and Carnegie led by CDAC Academic Partner Raymond Jeanloz and CDAC Director Russell Hemley, and including Paul Loubeyere of the CEA, France and G. W. (Rip) Collins of Livermore, has been awarded time at the National Ignition Facility (NIF) for fundamental science experiments beginning in 2012. The Berkeley-Carnegie...
December 15th, 2010
Interest in lightweight analogs of the novel superconductor magnesium diboride (MgB2) has motivated a search for new high pressure phases in metal boride systems. In the case of lithium monoboride (LiB), a previously unknown series of high pressure structures, some of which are expected to exhibit superconductivity, has been predicted...
December 9th, 2010
Direct measurements of the band gap of solid helium (4He) at high pressure are beyond the capabilities of typical optical techniques. This is because the band gap and associated excitations are masked by absorption by the gasket and anvils of the apparatus. Until now, there has not been an experimental technique with the energy and resolution...
October 19th, 2010
For the first time scientists have been able to watch nanoparticles grow from the earliest stages of their formation. The breakthrough was made possible by high-brightness and high-energy synchrotron radiation techniques developed in part by HPSynC. The work should lead to new ways to control nanocrystal growth, a result that will affect...
October 1st, 2010
Where does one go to learn the fundamental aspects of high pressure synchrotron work from experts in the field? To provide this opportunity, from September 15-18, CDAC and HPCAT held a short course entitled "High Pressure Synchrotron Techniques," designed for graduate students and postdoctoral fellows that may be new to synchrotron work. The goal...
September 16th, 2010
CDAC student Walter Uhoya (University of Alabama – Birmingham) and colleagues from ORNL, LLNL, and the University of Alabama, have shown that the structure of iron-based superconductor EuFe2As2 expands under pressure. In a paper published in the Journal of Physics: Condensed Matter, Uhoya, et al. report structural studies at HPCAT using designer...
September 16th, 2010
Researchers from the group of CDAC Academic Partner Rod Ewing at the University of Michigan and collaborators from the Geophysical Laboratory have demonstrated a new method to detect and quantitatively measure pressure-induced atomic disordering in pyrochlore oxides. This discovery provides new insight on the formation of of defects at extreme...
September 16th, 2010
With the availability of third-generation synchrotron x-ray facilities, the properties of nanoscale materials are now receiving increased attention. In particular, the high energy and brilliance coupled with the tight focus of the x-ray beams at HPCAT now make possible detailed structural studies of nanoscale solids. Lin Wang (HPSynC) and...
August 9th, 2010
AN INVESTIGATION OF THE STABILITY OF NICKEL-BEARING MINERALS IN ULTRAMAFIC-HOSTED HYDROTHERMAL VENT SYSTEMS
Rachael Hoover (University of Colorado) and Dionysis Foustoukos
A possible explanation for why life can thrive in extreme conditions, such as hydrothermal vents, is the presence of hydrocarbons. In ultramafic-hosted hydrothermal...
August 5th, 2010
A superconductor exhibits no resistance to electrical current when cooled below the critical temperature Tc, and developing superconductors with the highest possible transition temperatures is currently one of the grand challenges in materials physics. Until now, the highest Tc values have been observed in copper oxide based materials known as...
July 1st, 2010
The May/June, 2010 edition of Synchrotron Radiation News focused on high pressure research. Both of the technical reports in the edition showcased CDAC supported work and were coauthored by CDAC supported beamline personnel, including Zhenxian Liu, Guoyin Shen, Yang Ding, and Wenge Yang, as well as CDAC Academic Partner Tom Duffy (Princeton). The...
May 6th, 2010
An accurate measurement of the pressure is a fundamental aspect of all high pressure experiments, and there is a need for continuous development of new and better pressure scales. Pressure calibration has generally relied on the experimentally-determined equations of state or spectroscopic properties of internal standards such gold or ruby. In...
April 13th, 2010
Two new studies point to the important role that pressure plays in understanding and creating new ferroelectric materials. Lead-based relaxor ferroelectrics with complex perovskite structures exhibit a strong frequency-dispersive dielectric permittivity with a broad and smooth temperature dependence. Their high permittivity and high piezoelectric...
March 30th, 2010
The annual March meeting of the American Physical Society was held in Portland, Oregon from March 15-19, with CDAC researchers well represented among a number of sessions. Seven of the CDAC academic partner groups, along with Carnegie personnel, National Laboratory Partners and HPCAT/HPSynC staff presented 46 papers in 20 different sessions...
March 19th, 2010
The quality of measurements at extreme conditions is governed by the size of the analytical probe relative to the size of the samples. High energy synchrotron x-ray probes have been used in high-pressure studies for decades. However, at the existing dedicated high pressure facilities, the dimensions of probes have been limited to 2-5 microns,...
March 16th, 2010
Metallic glasses are unique materials at the cutting edge of materials research. New experiments now show that one can drastically change the nature of these glasses simply by applying pressure instead of by changing the composition. Structural transitions resulting from an increase in atomic coordination have been reported in a variety of...
January 27th, 2010
For the third year, the SSAA Program Symposium was hosted by the Carnegie Institution of Washington at its historic administration building in downtown Washington, DC. The meeting was held from January 20-22 and drew participants from around the country. Individual grant recipients and center directors from the three divisions of the program (High...
December 11th, 2009
Observations of van der Waals compounds in simple molecular systems at high pressure continue to bring surprises. Indeed, understanding the nature of bonding in these materials is not well understood. In the course of investigating the Xe-H2 system at high pressure, CDAC Research Scientist Maddury Somayazulu and co-workers from Carnegie and the...
October 5th, 2009
At the recent "21st Century Needs and Challenges in Compression Science" Workshop held at the Bishop's Lodge Ranch in Santa Fe, NM September 23-25, CDAC Director Russell Hemley chaired the Static Compression Panel, which included CDAC Advisory and Steering Committee members, as well as several CDAC collaborators.
September 16th, 2009
Hydrogen is the most abundant element in the cosmos, and its behavior at high pressure is crucial for a broad range of problems from condensed matter physics to astrophysics to stockpile stewardship. The structure of hydrogen in the dense molecular state remains challenging both experimentally and theoretically. Working with CDAC scientists at...
September 1st, 2009
Researchers from Caltech and UNLV, with the support of scientists from Carnegie, have demonstrated a new way to create in the laboratory a mineral that only exists in meteorites and deep below the Earth's crust. The discovery indicates that the formation of planets and certain minerals in the early solar system may have involved collisions...
September 1st, 2009
The new undulator operates with the existing one in tandem mode and was successfully commissioned on August 19, 2009. The dual undulator can deliver even brighter x-ray beams to the 16ID-B x-ray diffraction beamline and the 16ID-D x-ray spectroscopy beamline, providing flexibility in selecting x-ray energies while keeping the independent operation...
August 6th, 2009
The strength of the covalent H2 bond over a range of chemical and thermodynamic environments is of great interest. At extremely high pressure, hydrogen is expected to form a metallic phase and exhibit high temperature superconductivity. Despite these features, metallic hydrogen remains elusive as the pressures thought to be required to create it...
August 6th, 2009
At the recent AIRAPT-22 meeting, held in Odaiba, Tokyo, Japan from July 26 to July 31, CDAC was well represented, with 26 presentations made by CDAC-affilliated scientists from across the different sectors of the Center. CDAC Academic and National Laboratory partners, CDAC students, GL staff, HPCAT and HPSynC staff, and CDAC collaborators...
August 6th, 2009
Recent work carried out at Carnegie suggests that substantial amounts of the hydrocarbon material could exist in the deep Earth and be formed by inorganic (or abiogenic) processes. These hydrocarbons, which include natural gas and petroleum, could migrate from the mantle to the near-surface region and contribute to 'fossil fuel' reserves.
August 6th, 2009
ADSORPTION STUDIES OF THE AMINO ACIDS L-PHENYLALANINE AND L-DOPA TO THE RUTILE SURFACESalima Bahri (Barnard College), Caroline Jonsson, and Christopher Jonsson
The study of amino acid adsorption to mineral surfaces has implications for the origins of life as well as applications in medicine and research on possible sources of energy. It is...
May 28th, 2009
Understanding and ultimately controlling the intricate coupling between electrical conductivity and magnetism in colossal magnetoresistance (CMR) manganites remains a challenge, due to the coupling between lattice, charge, spin, and orbital degrees of freedom. Scientists from Carnegie, APS and Argonne, led by Yang Ding (HPSync) report new...
May 26th, 2009
Over 100 years ago Charles Edouard Guillaume, working at the International Bureau of Weights and Measures in France, discovered that certain alloys did not expand when heated, a behavior that came to be known as the Invar effect. Guillaume's discovery found immediate and lasting technological applications, and he was awarded the Nobel Prize in...
May 19th, 2009
Nearly 100 attendees from around the world came together for the High Pressure Synchrotron Science symposium, held May 6-8, 2009 at the Advanced Photon Source in conjunction with the 2009 APS User's Meeting. The mission of the symposium, which was sponsored by several groups including CDAC and HPSynC, was to bring the user community together to...
April 1st, 2009
The focus of the 6th annual LANSCE Neutron Scattering School is on phase transformations in bulk materials as investigated by neutron elastic and inelastic scattering. This years school will take place July 7-17, 2009. The application deadline is Monday, April 13, 2009.
March 30th, 2009
The mechanism by which atomic vibrations transport heat through an amorphous material or a glass has been a long-standing problem in condensed matter physics. Proposed mechanisms range from that of a minimum thermal conductivity where the Boltzmann equation is used with the mean free path set to a "lattice" constant, to a "fracton" model in which...
March 24th, 2009
The 2009 APS March Meeting was held from March 16-20 in Pittsburgh, PA. There were 24 abstracts submitted by CDAC affiliated scientists. Graduate students and post-docs from CDAC institutions who presented posters included Luke Schulenburger (Carnegie), Amy Lazicki (Carnegie), P. Ganesh (Carnegie), Shibing Wang (Stanford), Gopi Samudrala (...
March 6th, 2009
The CDAC Winter Workshop took place on February 27-28 at the Advanced Photon Source, Argonne National Laboratory. Forty-two graduate students and postdoctoral associates (including 28 graduate students from CDAC academic partner groups) attended a series of six tutorials given by CDAC academic partners and three lectures by scientists from NNSA...
March 6th, 2009
Silicon occupies a position in the periodic table at the border between metals and insulators, and has important technological applications. At low pressure, crystalline silicon adopts the diamond structure and is an indirect band-gap semiconductor. With increasing pressure, crystalline Si transforms from the diamond phase through a more highly-...
March 6th, 2009
In the search for new alloys, metallurgists are guided by the empirical Hume-Rothery rules, which state that two elements can form an alloy only if they are similar in atomic size and electronegativity. Cerium atoms are 28% bigger than aluminum atoms, and have a significantly lower electronegativity, and on the basis of the Hume-Rothery rules,...
February 2nd, 2009
A international group including Zhenxian Liu (Carnegie) and CDAC Partner Yangzhang Ma (Texas Tech University) has discovered a new chemical compound that consists of a single element―boron. Chemical compounds are conventionally defined as substances consisting of two or more elements, but these results show that at high pressure and temperature,...
November 14th, 2008
Researchers at the Geophysical Laboratory have developed a technique for improving the properties of diamond, simplifying the process of making high-quality diamond for scientific applications, electronic components, cutting tools, and even quantum computers. Impurities and defects in diamond can be purged by annealing, but this can turn diamond...
October 29th, 2008
The Workshop on Advances in High-Pressure Science using Synchrotron X-rays, held on October 4th at the National Synchrotron Light Source, was a tremendous success. The workshop was organized in honor of Jingzhu Hu and Quanzhong Guo in celebration of their retirement after up to 18 years of dedicated service to the high-pressure community. Hu was...
October 21st, 2008
The key to understanding Earth's evolution, including how our atmosphere gained oxygen and how volcanoes and earthquakes form is too look deep, really deep, into the lower mantle some 400 to 1,800 miles (660 to 2,900 kilometers) below the surface. Researchers , led by Alexander Goncharov (Geophysical Laboratory) and including Carnegie Summer...
September 2nd, 2008
The N-N triple bond in molecular nitrogen is one of the strongest and most stable chemical bonds in nature, giving rise to the two most commonly observed states, the solid and liquid. Molecular nitrogen itself, however, has shown a surprising degree of polymorphism, leading to a complex phase diagram that is still incomplete in the high pressure...
August 15th, 2008
A workshop/symposium honoring the service of Jingzhu Hu and Quanzhong Guo at the NSLS X17 beamlines, Brookhaven National Laboratory, will be held on October 4, 2008 at Brookhaven. For 18 years, the two have been instrumental in pioneering x-ray diffraction techniques for high pressure research.
August 14th, 2008
SEARCHING FOR THE ORIGINS OF EXTRATERRESTRIAL INSOLUBLE ORGANIC MATTEREmily Heying (Wartburg College) and George Cody
The Insoluble Organic Matter (IOM) found in meteorites, particularly carbonaceous chondrites, is an abundant reservoir for carbon material. Although the chemical structure of this IOM has been analyzed, questions still...
August 13th, 2008
Xiao-Jia Chen and colleagues from the Geophysical Laboratory, in collaboration with scientists from the Chinese University of Hong Kong and South China University of Technology, have predicted from first principles the superconducting properties of the hydrogen-rich molecular compound silane (SiH4). A gas at ambient conditions, solid silane adopts...
August 11th, 2008
Molecular oxygen (O2) changes its form dramatically with compression, transforming to a solid with spectacular colors, and eventually becoming metallic and superconducting at sufficiently high pressures. The underlying mechanism for these remarkable phenomena has been a source of debate for decades, in particular the origin of the recently...
August 11th, 2008
A collaborative research team from multiple institutions, including Harbin Institute of Technology, Argonne National Laboratory, Harvard University, and Geophysical Laboratory has discovered unexpected dynamics and volume expansion associated with pressure-induced crystallization of amorphous selenium. The development and application of the state-...
June 5th, 2008
Since the discovery in 1986 of high-temperature superconductivity in layered cuprates, the secrets of this remarkable phenomenon have steadily emerged. From the time of the earliest reports, it has been well recognized that the superconducting transition temperature is highly sensitive to the level of chemical doping, a necessary prerequisite to...
June 5th, 2008
A Workshop on Understanding Condensed Matter Dynamics at the Microscopic Level was held at the Advanced Photon Source, Argonne National Laboratory on June 23-24, 2008. It was organized by Yogi Gupta (WSU), Christian Mailhiot (DOE-NNSA), and Dennis Mills (APS).
March 13th, 2008
The chemical combination of noble (platinum group) metals with elemental nitrogen represents a significant synthetic challenge, due to the inert nature of both the metal and the nitrogen-nitrogen triple bond. Recent high pressure work has shown, however, that a number of MN2 compounds (M = platinum group metal) are stable in the diamond anvil...
March 6th, 2008
For the second year in a row, the annual SSAA Program Symposium was hosted by the Carnegie Institution of Washington at its historic administration building in downtown Washington, DC. The meeting was held from February 26-28 and drew participants from around the country. Individual grant recipients and center directors from the three divisions of...
January 28th, 2008
In most cases, modern piezoelectric materials suitable for technological applications are compositionally complex solid solutions based on the endmember lead titanite, PbTiO3, with up to six different metal cations substituting on the two available sites of a perovskite-based structure. Morphotropic phase boundaries separating the distorted...
December 5th, 2007
Supported by beam time provided by CDAC and other members of the HPCAT consortium as well as HPCAT itself, a group from the Institute for Shock Physics (Washington State University , Pullman, WA) have succeeded in monitoring shock compression in real time using synchrotron x-rays. The Shock Physics group, led by Yogendra Gupta, a CDAC advisory...
December 5th, 2007
The Lujan Neutron Scattering Center, part of the Los Alamos Neutron Science Center (LANSCE) recently held a workshop entitled "Enhanced National Capability for Neutron Scattering." Hosted by the University of California, San Diego on September 5-7, the purpose of the workshop was to review and approve the strategic plan for the Lujan Center in the...
September 27th, 2007
This week's issue of Physical Review Letters reports new class of measurements on the high-pressure behavior of spin and charge density waves in single crystal metals. Using high-resolution x-ray microdiffraction techniques at HPCAT, Yejun Feng from the University of Chicago and collaborators from Argonne National Laboratory and University...
September 5th, 2007
Pure substances that form glasses are quite common, but up to now the formation of a bulk glass formed through vitrification of a pure monatomic elemental liquid has been elusive. When crystal nucleation times are long compared to the time for assembly of amorphous forms, then the glassy state can be observed. A key requirement is the lowering of...
July 30th, 2007
Brookhaven National Laboratory recently hosted a workshop on July 17-18, 2007 to provide the NSLS user community an opportunity to learn about the status and plans for NSLS-II, the medium-energy storage ring that is designed to provide x-rays with vastly improved brightness and flux compared to the current NSLS. The workshop featured presentations...
July 23rd, 2007
Former Carnegie predoctoral fellow Sébastien Merkel (formerly from the University of California, Berkeley, now at CNRS and the University of Science and Technology of Lille, France - pictured bottom right) and a group that included CDAC partners Tom Duffy (Princeton) and Hans-Rudolf Wenk (Berkeley), and CDAC student Lowell Miyagi (Berkeley) as...
June 28th, 2007
McMahan and LeSar predicted the formation of a 'polymeric' network structure of nitrogen in 1985 at LANL. This work was extended by Mailhiot and colleagues at LLNL in 1992. In a recent issue of the Journal of Chemical Physics, former CDAC Research Scientist Eugene Gregoryanz (now at the University of Edinburgh) and colleagues from Carnegie, the...
May 1st, 2007
The 2007 Meeting of Study of Matter at Extreme Conditions (SMEC) from April 15-20 in Miami was a great success. The conference was sponsored by CeSMEC and CDAC, and featured 46 scientific presentations from CDAC affiliated scientists (including 41 abstracts and 5 Symposia Panel Talks).
April 12th, 2007
The structural and vibrational properties of metals and alloys at high pressure is a priority area in modern materials science research. CDAC-supported graduate student Matthew Lucas (Caltech), and fellow Caltech student Alexander Papandrew, along with their advisor, Caltech professor and CDAC partner Brent Fultz, and HPCAT scientist Michael Hu...
March 15th, 2007
A wide variety of CDAC sponsored research was presented at the recent APS March Meeting, held March 5-9 in Denver, CO, including three invited and twenty-four contributed talks. Invited talks were given by Carnegie staff member Ronald Cohen (Geophysical Laboratory), partner Kanani Lee (New Mexico State University) and former post-doctoral...
March 15th, 2007
In the March 9, 2007 edition of Physical Review Letters, a group from Seoul National University and the GSECARS and HPCAT sectors at the Advanced Photon Source report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (with nominal composition Li2B4O7) at high pressure.
March 2nd, 2007
Metals and alloys often exist in more than one crystal structure, the fcc and bcc structures of iron being a familiar example of such polymorphism. When metallic materials exist in an amorphous form, would a parallel 'polyamorphism' be possible? So far, polyamorphic phase transitions in the glassy state have been observed only in glasses involving...
March 2nd, 2007
High-temperature superconductivity in cuprate superconductors was discovered almost exactly 20 years ago, but a satisfactory theoretical explanation for this phenomenon is still lacking. Observations of the isotope effect in conventional superconductors (Nb3Ge for example) have played an important role in establishing the electron-phonon...
February 26th, 2007
Scientists at HPCAT have observed a unique type of high-pressure phase transition in vanadium that has not yet been documented for a pure element. At about 60 GPa, single crystal vanadium undergoes a cubic-to-rhomohedral transition in which the volume does not change at the transition. The displacive phase transformation is quite similar in nature...
February 15th, 2007
The third annual SSAA Program Symposium was hosted by the Carnegie Institution of Washington at its historic administration building in downtown Washington, DC from February 5-7. Center directors and individual grant recipients from the three divisions of the program (High Energy Density Physics, Low Energy Nuclear Science and Materials Properties...
December 4th, 2006
A highly successful symposium, "Materials Research at High Pressure," was held at the 2006 MRS Fall Meeting in Boston. The symposium was jointly sponsored by Livermore National Laboratory and CDAC, and featured 59 scientific presentations (42 oral presentations and 17 posters). Invited speakers included Jonathan Crowhurst of Livermore, Vadim...
November 28th, 2006
Material emissivity measurements at extreme conditions can provide fundamentally important data that allow the measurement of temperature on short time scales, which is crucial for the complete characterization of dynamic compression events. For opaque materials such as metals, reflectivity measurements are necessary and must be conducted under...
October 27th, 2006
Metal dichalcogenides are excellent solid lubricants due to their graphitic structure and weak inter-layer bonding, which combine to facilitate shear. One of the typical metal dichalcogenides is tungsten disulfide (WS2), which can be either dispersed into liquid lubricants, like graphite, to reduce the friction and wear between moving surfaces; or...
October 20th, 2006
Wendy Mao, a former CDAC graduate student now at Los Alamos National Laboratory, together with Ho-kwang Mao, Jinfu Shu, Russell J. Hemley (Geophysical Laboratory), Yue Meng, Michael Hu, Paul Chow (HPCAT), Peter Eng (University of Chicago) and Yong Q. Cai (National Synchrotron Radiation Research Center, Taiwan) have carried out measurements on H2O...
August 3rd, 2006
A long-standing problem has been whether the high pressure phase of iron, hexagonal close-packed, hcp-Fe, or ε-Fe is magnetic or not. Experiments since the 1960s have found no unambiguous evidence for magnetism, but first-principles theory says it should be antiferromagnetic. First-principles calculations of the hyperfine fields (HF) however,...
May 26th, 2006
The flow of heat in Earths deep interior plays an important role in the dynamics, structure, and evolution of the planet. Heat from the very hot core can flow outward by convection, radiation, and conduction. The relative amount of heat flow from these mechanisms is currently under debate. Experiments performed at the Carnegie Institution's...
May 24th, 2006
We are pleased to report that the CDAC-sponsored workshop 'Synergy of 21st Century High-Pressure Science and Technology', April 29 to May 1, 2006 at the Advanced Photon Source of the Argonne National Laboratory was a great success. Convened to explore current and future opportunities in 21st century high-pressure science and technology, the...
April 26th, 2006
The discovery of new metal nitrides by CDAC summer undergraduate intern Andrea F. Young (on left in picture at HPCAT) has been published in the April 21st issue of Physical Review Letters. As the first author of the paper, Andrea published the work with E. Gregoryanz (former CDAC Scientist, now at the University of Edinburgh, right in picture), C...
March 27th, 2006
On April 29-May 1, 2006, CDAC will be a co-sponsor of the workshop "Synergy of 21st Century High Pressure Science and Technology," held at the Advanced Photon Source. Similar to last year's CDAC Summer School, this will be held at the APS and will have a strong student focus as well as talks by leading researchers.
February 13th, 2006
Synthesis of superhard materials under conditions of very high pressures and temperatures is the Holy Grail of Materials Sciences. Noble metals do not easily form compounds with other elements, but this can be changed under pressure. Alexander Goncharov (GL, former LLNL) and his coauthors at Lawrence Livermore National Laboratory (J. C. Crowhurst...
February 3rd, 2006
Sebastien Merkel and colleagues from University of California-Berkeley, Princeton University, and the Geophysical Laboratory recently reported new insights into the plastic behavior of post-perovskite deep in the Earth's interior in a paper published in Science. Under the pressures of the core-mantle boundary (2900km below the surface), the main...
November 29th, 2005
Los Alamos National Laboratory's Zhongwu Wang and colleagues recently reported new insights into the behavior of wurtzite-type ZnS with respect to structural stability, phase transformation and fracture in the November 13th advanced published paper at the journal Nature Materials. Wurtzite-type ZnS nanobelts have a {210}-dominated surface...
November 18th, 2005
This fall, CDAC members participated in two workshops held at COMPRES sponsored facilities. The Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures was sponsored by COMPRES and held on October 21-23, 2005 at HPCAT. It was organized by Haozhe Liu (HPCAT), Rudy Wenk (University of California, Berkeley) and Thomas...
July 19th, 2005
CDAC members Jung-Fu Lin, Viktor Struzhkin, and Steve Jacobsen and other colleagues from CDAC-Carnegie, HPCAT, and State University of New York at Stony Brook, recently reported new insights into the behavior of iron deep in the Earth's interior near the core in the July 21st issue of the journal Nature. Under the extreme pressure and temperature...
July 11th, 2005
The first CDAC Summer School, held June 1-3, 2005 at the Advanced Photon Source of the Argonne National Laboratory, was by every measure a great success. 33 young scientists from around the country attended and were taught by leading scientists from academia and the National Labs about the exciting field of high-pressure materials science.
June 24th, 2005
New experiments conducted by a team from the from Geophysical Laboratory and the Advanced Photon Source, Argonne National Laboratory, led by Dr. Jung-Fu Lin, and reported on in an article in Science, suggest that the core of the Earth may contain more light elements than previously thought. Sound velocities of hexagonal close-packed iron (hcp-Fe...
May 17th, 2005
New Diamond Technique Produces 10-carat Diamond
Very Large Diamonds Produced Very Fast
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May 16th, 2005
In a new article in Physical Review Letters, Eugene Gregoryanz and his colleagues from Geophysical Laboratory and HPCAT at the Advanced Photon Source, Argonne National Laboratory report on the behavior in sodium when squeezed to 1.2 million atmospheres. High-pressure high-temperature synchrotron diffraction measurements reveal a maximum on the...
May 4th, 2005
H2O consists of the first and third most abundant elements in the solar system and is ubiquitous in the cosmos. The phase diagram and properties of H2O at high pressure and temperature conditions relevant to planetary interiors are thus crucial for modeling planetary interiors and for identifying and understanding numerous chemical reactions at...
April 22nd, 2005
P-V data and fit below 19.6 GPa and corresponding structural models (solid square: cubic phase; solid circle: rhombohedral phase).
Neutron diffraction patterns (with background removed) collected at different pressures: (a) 8.2 GPa; (b) 13.0 GPa; and (c) 20.3 GPa. The solid lines are the calculated patterns. Diffraction patterns of the super-...
April 22nd, 2005
The neutron experiments carried out at Intense Pulse Neutron Source (IPNS), Argonne National Laboratory and Los Alamos Neutron Science Center (LANSCE), Los Alamos National Laboratory, reveal surprising new findings in Fe1-xO. Variable pressure-temperature neutron diffraction techniques were applied to investigate the magnetism of the rhombohedral...
April 19th, 2005
The CDAC Summer School had been established to provide an introduction for graduate students and postdoctoral researchers to high pressure-temperature materials research. We aim to explore the chemical and physical fundamentals of matter at high densities, and illustrate how static and dynamic experiments, along with condensed matter theory, can...
February 16th, 2005
Ultrafast ~1 GPa shock compression of self-assembled all-trans hydrocarbon monolayers (SAMs) with an even number (18) or an odd number (15) of carbon atoms was studied with vibrational sum-frequency generation spectroscopy (SFG). Both SAMs are in the long-chain limit, generally taken to be ≥ 14 carbon atoms, so the significant difference is the...
January 25th, 2005
Methane gas has been synthesized from wustite, calcite and water at high temperatures and pressures in the diamond anvil cell, demonstrating abiogenic pathways for the formation of hydrocarbons in the Earth's deep interior. Bubbles formed in the mixture (bottom, left and near the center in the photomicrograph above) upon decompression to 0.5 GPa...
December 22nd, 2004
CDAC graduate student Nick Cunningham (University of Alabama-Birmingham) has shown that Pr metal at high pressure undergoes dramatic grain growth as the metal passes through the fcc-to-alpha uranium structural phase transition (Cunningham, Velisavljevic and Vohra, Phys. Rev. B, in press). At 16.0 GPa smooth diffraction rings indicate a highly...
October 23rd, 2004
Cold compression of carbon nanotubes at 75 GPa results in the formation of a superhard hexagonal carbon polymorph that has a different structure than hexagonal diamond [Wang, et al., Proc. Natl. Acad. Sci 101, 38, 13699 (2004]. This new phase is quenchable to ambient pressure and has an experimentally determined bulk modulus of 447 GPa, slightly...
September 23rd, 2004
Nuclear resonant inelastic x-ray scattering (NRIXS) spectroscopy of iron at high temperature and pressure has been used to provide independent confirmation that the Planck radiation function is a reliable indicator of the temperature in the laser heated diamond anvil cell. Using the principle of detailed balance and the peak intensities from the...
July 29th, 2004
An unusual polymorph of the accessory mineral chromite, (Fe,Mg)(Cr,Al)2O4, has recently been discovered in the shock veins of the Suizhou meteorite. This backscattered electron image of a grain of the meteorite shows light-colored bands corresponding to the post-spinel, calcium ferrite (CF)-type phase of chromite. The higher-pressure calcium...
June 12th, 2003
The Carnegie group has mounted a major initiative to create the next generation high-pressure devices based on large single-crystal diamond anvils grown by chemical vapor deposition (CVD). The above photograph shows a synthetic brilliant cut single-crystal diamond grown by CVD. About 2.5 mm high, this crystal was grown in about 1 day at Carnegie....
