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We report density-functional based molecular dynamics simulations, that show that, with increasing pressure, liquid carbon undergoes a gradual transformation from a liquid with local three-fold coordination to a 'diamond-like' liquid. We…

Other Condensed Matter · Physics 2009-11-10 Luca M. Ghiringhelli , Jan H. Los , Evert Jan Meijer , A. Fasolino , Daan Frenkel

We present a combined experimental and theoretical study on the quasi-one-dimensional organic conductor (TMTTF)$_2$PF$_6$, and elucidate the variation of its physical properties under pressure. We fully resolve the crystal structure by…

We report the structural, vibrational and electrical transport properties up to 16 GPa of the 1T-TiTe2, a prominent layered 2D system, which is predicted to show a series of topologically trivial - nontrivial transitions under hydrostatic…

Yttrium superhydrides has attracted much attention due to their multiple stoichiometries and excellent superconductivities under high pressure. Especially, YH9 have a Tc of 243 K, which is the second highest Tc among all binary hydrides. It…

Superconductivity · Physics 2023-02-10 Mingyang Du , Zonglun Li , Defang Duan , Tian Cui

We introduce a novel method that combines the accuracy of Quantum Monte Carlo simulations with ab-initio Molecular Dynamics, in the spirit of Car-Parrinello. This method is then used for investigating the structure of a two-dimensional…

Computational Physics · Physics 2017-05-16 Francesco Calcavecchia , Thomas D. Kühne , Markus Holzmann

We have performed ab initio calculations for new high-pressure phase of Ca-VI between 158-180 GPa. The study includes elastic parameters of mono- and poly-crystalline aggregates, electronic band structure, lattice dynamics and…

Superconductivity · Physics 2015-05-19 M. Aftabuzzaman , A. K. M. A. Islam

Ab initio molecular dynamic method within the framework of density functional theory is applied to analyze the structural and electronic properties of crystalline molecular hydrogen at temperature 100\,K. Pressure, pair correlation function…

Materials Science · Physics 2022-01-12 I. Saitov

The effects of pressure on the crystal structure of the three known polymorphs of magnesium sulfate have been theoretically study by means of DFT calculations up to 45 GPa. We determined that at ambient conditions gamma MgSO4 is an unstable…

Materials Science · Physics 2017-05-31 A. Benmakhlouf , D. Errandonea , M. Bouchenafa , S. Maabed , A. Bouhemadou , A. Bentabet

Pressure-induced transitions from ordered intermetallic phases to substitutional alloys to semi-ordered phases were studied in a series of bismuth tellurides. Using angle-dispersive x-ray diffraction, the compounds Bi4Te5, BiTe, and Bi2Te…

Materials Science · Physics 2016-06-28 I. Loa , J. -W. G. Bos , R. A. Downie , K. Syassen

A comparative computational study of stability of candidate structures for an as yet unknown silver dichloride AgCl2 is presented. It is found that all considered candidates have a negative enthalpy of formation, but are unstable towards…

Materials Science · Physics 2022-01-25 A. Grzelak , W. Grochala

High pressure in-situ synchrotron X-ray diffraction experiments were performed on Ag2Te up to 42.6 GPa at room temperature and four phases were identified. Phase I ({\beta}-Ag2Te) transformed into phase II at 2.4 GPa, and phase III and…

Materials Science · Physics 2015-05-01 Zhao Zhao , Shibing Wang , Haijun Zhang , Wendy L. Mao

Phase stability of various phases of MX (M = Ti, Zr; X = C, N) at equilibrium and under pressure is examined based on first-principles calculations of the electronic and phonon structures. The results reveal that all B1 (NaCl-type) MX…

Materials Science · Physics 2013-09-25 V. I. Ivashchenko , P. E. A. Turchi , V. I. Shevchenko

The pressure-induced structural transition in fcc C$_{60}$ fullerene by shock compression and rapid quenching is investigated by a semi-empirical tight-binding molecular dynamics simulation, adopting a constant-pressure scheme and a method…

Computational Physics · Physics 2007-05-23 Akihito Kikuchi , Shinji Tsuneyuki

We report experimental evidence for pressure instabilities in the model multiferroic BiFeO3 and namely reveal two structural phase transitions around 3 GPa and 10 GPa by using diffraction and far-infrared spectroscopy at a synchrotron…

Materials Science · Physics 2011-07-26 R. Haumont , P. Bouvier , A. Pashkin , K. Rabia , S. Frank , B. Dkhil , W. A. Crichton , C. A. Kuntscher , J. Kreisel

The structural properties under hydrostatic pressure up to 3 GPa of the layered rare earth carbide halide superconductor Y2C2I2 are studied by neutron powder diffraction at room temperature. The compressibilities are anisotropic, such that…

Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures…

Recent DFT (density functional theory) simulations showed that metals have a hitherto overlooked symmetry termed "hidden scale invariance" [Hummel {\em et al.}, Phys. Rev. B {\bf{92}}, 174116 (2015)]. According to isomorph theory, this…

Materials Science · Physics 2019-03-06 Laura Friedeheim , Jeppe C. Dyre , Nicholas P. Bailey

We present theoretical study of relative stability as well as of the magnetic and electronic properties of AgF2 and CuF2, in two related structural forms: orthorhombic (ambient pressure form of AgF2) and monoclinic (ambient pressure form of…

Materials Science · Physics 2024-03-28 Daniel Jezierski , Wojciech Grochala

In this paper we report parallel in situ neutron powder diffraction and Tc(P) measurements versus pressure on the same MgB2 sample in a He-gas apparatus to 0.6 GPa; in addition, we present Tc(P) measurements in a helium-loaded…

Superconductivity · Physics 2007-05-23 J. S. Schilling , J. D. Jorgensen , D. G. Hinks , S. Deemyad , J. Hamlin , C. W. Looney , T. Tomita

Structural phase transitions accompanied by incommensurate and commensurate charge density wave (CDW) modulations of unconventional nature have been reported in BaNi$_2$As$_2$, a nonmagnetic cousin of the parent compound of Fe-based…