The Elasticity and Equations of State thrust in CDAC aligns with the paramount need of the NNSA labs for accurate pressure-volume-temperature relations and other elastic properties at extreme conditions for a broad range of materials. CDAC advances in Y1 included studies of the phonon thermodynamics and elastic behavior of GaAs at high temperatures and pressures by former CDAC student Jane Herriman (now at LLNL) and Brent Fultz (Caltech) [J. E. Herriman and B. Fultz, Phys. Rev. B 101, 214108 (2020)]. CDAC Research Scientist Muhtar Ahart worked with collaborators to perform Brillouin scattering measurements of the elastic properties of amber glass [S. Tkachev et al., Jap. J. Appl. Phys. 60, SDDA04 (2021)]. EOS studies also included x-ray measurements of metal alloys by CDAC student M. Lv and CDAC
Academic Partner Susannah Dorfman (Michigan State) [M. Lv et al. J. Geophys. Res. 124, DOI: 10.1029/2020JB020660 (2020)].

[1] J. E. Herriman and B. Fultz, Phys. Rev. B 101, 214108 (2020);  [2] S. Tkachev et al., Jap. J. Appl. Phys. 60, SDDA04 (2021);  [3] M. Lv et al. J. Geophys. Res. 124, DOI: 10.1029/2020JB020660 (2020)

The Plasticity, Strength, and Deformation Thrust is another important area of study in CDAC as it is central to many problems associated with Stewardship Science. Numerous advances were made in Y1, led by Lowell Miyagi (Utah) and Susannah Dorfman (Michigan State). CDAC student Ben Brugman (Michigan State) completed his PhD thesis, which covered numerous topics within this Thrust. Advances included experimental studies of deformation of Earth materials as analogs for materials behavior of systems of interest to the NNSA. This includes studies led by CDAC student Samantha Couper (Utah), who also completed her PhD thesis and is now a postdoc at LANL [S. Couper et al., in Mantle Convection and Surface Expressions, in press]. Another study from Utah is a collaboration with LBL and UCSC [C. Vennari et al., Am. Mineral. 106, 1045-1052 (2021)]. Advances in experimental techniques included an improved setup for radial diffraction experiments at high pressures and high temperatures in resistive graphite-heated diamond anvil cells led in part by the Utah group [J. Immor et al., Rev. Sci. Instrum. 91, 045121 (2020)]. Progress was also made on development of ultrafast compression texture analysis (Milestone #6), again led by the Miyagi (Utah) with
beam time at HPCAT. CDAC partners and collaborators in this Thrust took part in a LANL workshop focusing on data science and dynamic compression experiments [C. M. Sweeney et al., Data Science and Computation for Rapid and Dynamic Compression Experiment Workflows at Experimental Facilities Workshop Report, LA-UR-20-27469 (2021)].

[1] B. Brugman, Strength, Deformation and Compression Behavior of Tungsten Carbide, Krypton and Xenon.  PhD Dissertation: Michigan State University (2021);  [2] S. Couper, Application of Novel Methods for Investigating High Pressure and Temperature Deformation of Earth Materials.  PhD Dissertation:  University of Utah (2021);  [3] S. Couper, et al. Front. Earth Sci. 8, 540449 (2020);  [4] C. A. Vennari, et al., Am. Mineral. 106, 1045-1052 (2021);  [5] J. Immor et al., Rev. Sci. Instrum. 91, 045121 (2020)];  [6] C. M. Sweeney et al., LANL Workshop Report LA-UR-20-27469 (2021).

The Complex Materials thrust targets studies of multi-component and multi-phase materials exhibiting order and composition over a range of length scales such as nanophase, mesoscopic, composite, and polyphase materials, including new materials produced by advanced (e.g., additive) manufacturing methods. Advances included pressure induced enhancement of thermoelectric properties led in part by CDAC Research Professor Ravhi Kumar in collaboration with LANL and HPCAT [J. L. Baker et al., J. Phys. Chem. Lett. 12, 1046-1051 (2021)]. Former Northwestern student Ryan Klein discovered pressure-induced collapse of magnetic order in jarosite [R. A. Klein et al., Phys. Rev. Lett. 125, 077702 (2020)]. A UIC collaboration with students at Penn State led to the development of methods to fabricate diamond encapsulated silicon fibers by chemical vapor deposition [A. T. Hendrickson et al., AIP Advances 10, 095009 (2020)].

[1] J. L. Baker et al., J. Phys. Chem. Lett. 12, 1046-1051 (2021);  [2] R. A. Klein et al., Phys. Rev. Lett. 125, 077702 (2020);  [3] A. T. Hendrickson et al., AIP Advances 10, 095009 (2020).

The Extreme Chemistry Thrust explores the frontier of chemical bonding structure and related properties of the elements at extreme conditions, including the ‘New Periodic Table’ under pressure. Two ‘tri-lab’ theoretical studies spearheaded by Eva Zurek (Buffalo) highlighted work in this Thrust. The first involved Buffalo, UIC, and LLNL, which uncovered new chemistry in the Li-F-H ternary system, important in particular for dynamic compression experiments involving lithium fluoride and hydrogen led by former CDAC student Tiange Bi [T. Bi et al. J. Chem. Phys. 154, 124709 (2021)]. A second tri-lab study led by CDAC postdoc Katie Hilleke was a collaboration between Buffalo, LLNL, and LLE to identify novel structures and bonding in boron at megabar pressures [K. P. Hilleke et al., Phys. Rev. Mater. 5, 053605 (2021)]. We also highlight work that involved synchrotron IR measurements at NSLS-II on the synthesis of atomically thin hexagonal diamond with compression that was led in part by former CDAC partner Wendy Mao (Stanford) [F. Ke et al., Nano Lett. 20, 5916-5921 (2020)]. Finally, progress on Milestone #6, “Extreme states of water” included studies of H2O ice at megabar pressures using synchrotron far infrared spectroscopy at FIS NSLS-II.

[1] T. Bi et al., J. Chem. Phys. 154, 124709 (2021);  [2] K. P. Hilleke et al., Phys. Rev. Materials 5, 053605 (2021);  [3] F. Ke et al., Nano Lett. 20, 5916-5921 (2020).

The Defects and Ion Irradiation Thrust explores the effect of intense ionizing radiation on materials, including the formation of defect and other structures in materials on exposure to ion radiation as well as the effects of multiple extreme environments such as irradiation in combination with high pressures and temperatures. Leading this Thrust is Maik Lang (Tennessee), in the following topics: Comparing the behavior of carbide and oxide compounds under dense electronic excitations (CDAC students William Cureton and Zach Chaney); analysis of high-temperature response of carbides after exposure to dense electronic excitations (CDAC students Zach Chaney and John Hirtz); and coupling high-pressure cells with relativistic heavy ion irradiation to study response of materials to multiple extremes (CDAC student John Hirtz). Annealing of ion tracks in apatite under pressure was characterized insitu by small angle x-ray scattering [D. Schauries et al., Sci. Rep. 10, 1367 (2020)]. Progress on Milestone #2 on pressurized UO2 doped with lanthanide atoms was limited by the pandemic and related difficulties of remotely handling actinide oxides. The group has shifted its focus to appropriate surrogate materials (doped CeO2) [W. Cureton, et al., Quantum Beam Sci. 5, 19 (2021)]. We have studied the behavior of these materials under dense electronic excitations and will study their phase transformation behavior and bulk moduli during the next allotted beamtime at HPCAT.

[1] D. Schauries et al., Sci. Rep.10, 1367 (2020).

The Phase Transition Dynamics Thrust addresses the grand challenge of determining kinetics of phase transitions in materials over a broad range of time scales and the development of time-dependent, metastable phase diagrams. Both synchrotron x-ray diffraction at ALS and synchrotron infrared spectroscopy at FIS were employed to elucidate the complex phase transition pathway in hydrated iron (II) sulfate at high pressure [O. S. Pardo et al., Am. Mineral., in press]. This work is closely related to other thrust areas such as EOS and Elasticity; Plasticity, Strength and Deformation; and Defects and Ion Irradiation. Work also includes theoretical studies, including advancing non-equilibrium molecular dynamics (Milestone #4) that is underway in collaboration with scientists at LLNL and that also involves experiments at NIF on Fe to 20 TPa pressures [Kraus et al., Science, submitted]. Topics in this Thrust are also covered in the LANL workshop report mentioned above [C. M. Sweeney et al., LA-UR-20-27469 (2021)].

[1]  R. A. Kraus, et al., Manuscript in preparation;  [2] C. M. Sweeney et al., LANL Workshop Report LA-UR-20-27469 (2021).

The Superconductivity and Electronic and Magnetic Phenomena Thrust focuses on the remarkable changes in condensed matter in materials associated with increasing pressure, leading to novel materials and phenomena such as high temperature superconductivity that was discovered in CDAC in 2018. Considerable progress was made in this Thrust during Y1, including both experimental studies of novel hydrides using synchrotron x-ray diffraction and infrared spectroscopy (Milestone #3) as well as a variety of theoretical studies. A collaboration with University of Texas at Dallas identified hole-doping by carbon as responsible for the newly discovered room-temperature superconductivity observed in carbonaceous sulfur hydride [Y. Ge et al., Mater. Today Phys. 15, 100330 (2020)]. Single crystal x-ray diffraction and the equation of state of the material was determined to 180 GPa at HPCAT in a multi-laboratory collaboration led by UIC [A. Lamichhane et al., J. Chem. Phys. 155, 114703 (2021).]. Theoretical studies of new superconductors included the prediction of an alkali metal borosilicide that is metastable and superconducting at 1 atm [X. Cui et al. J. Phys. Chem. C 124, 14826-14831 (2020)]. Studies of novel magnetic and electronic materials include numerous investigations by CDAC collaborator Janice Musfelt and her students using high-pressure synchrotron IR spectroscopy at FIS NSLS-II [Q. Chen et al.,Phys. Rev. Mater. 4, 064409 (2020); N. Harms et al., NPJ Quantum Mater. 5, 56 (2020); A. Clune et al., Inorg. Chem. 59, 10083-10090 (2020); K. A. Smith, et al., Phys. Rev. B 104, 064106 (2021)]. New collaborations with the group of James Hamlin and former CDAC student Jinhyuk Lim have provided new insights on superconductivity in the novel materials Be22Re [J. Lim et al., Phys. Rev. B 104, 064505] and WB2 [J. Lim et al., arXiv:2109.11521]. Activities in this Thrust included the development and refinement of diamond-anvil cells led by UIC for measurements at multimegabar pressures in high magnetic fields in collaboration with a team at the NHMFL and former CDAC partner Yogesh Vohra [A. D. Grockowiak et al., arXiv:2006.03004.; M. Ahart et al., in preparation] (Milestone #5).

[1] M. Somayazulu et al., Phys. Rev. Lett. 122, 027001 (2019);  [2] Y. Ge et al., Mater. Today Phys. 15, 100330 (2020);  [3] A. Lamichhane et al., J. Chem. Phys. 155, 114703 (2021);  [4] X. Cui et al., J. Phys. Chem. C 124, 14826-14831 (2020);  [5] Q. Chen et al., Phys. Rev. Mater. 4, 064409 (2020);  [6] N. Harms et al., NPJ Quantum Mater. 5, 56 (2020);  [7] A. Clune et al., Inorg. Chem. 59, 10083-10090 (2020);  [8] A. D. Grockowiak et al., arXiv:2006.03004;  [9] M. Ahart, et al., In preparation;  [10] J. Lim, et al., arXiv:2019.11521.