Quantum and temperature effects on crystal structure of superhydride: A path integral molecular dynamics study

Abstract

By classical and path-integral molecular dynamics simulations, we study the pressure-temperature ($P$-$T$) phase diagram of LaH${}_{10}$ to clarify the impact of temperature and atomic zero-point motions. We calculate the XRD pattern and analyze the space group of the crystal structures. For 125 GPa $\le P\le$ 150 GPa and $T=300$ K, we show that a highly symmetric $Fm\bar{3}m$ structure, for which superconductivity is particularly favored, is stabilized only by the temperature effect. On the other hand, for $T=200$ K, the interplay between the temperature and quantum effects is crucial to realize the $Fm\bar{3}m$ structure. For $P=$100 GPa and $T=$300 K, we find that the system is close to the critical point of the structural phase transition between the $Fm\bar{3}m$ structure and those with lower symmetries.

arXiv comment6 pages, 6 figures

References in corpus (26)

• Conventional superconductivity at 203 K at high pressures
• Superconductivity at 250 K in lanthanum hydride under high pressures
• Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures
• Observation of the Wigner-Huntington Transition to Solid Metallic Hydrogen
• Crystal Structure of 200 K-Superconducting Phase of Sulfur Hydride System
• A Perspective on Conventional High-Temperature Superconductors at High Pressure: Methods and Materials
• Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
• Anomalous high-temperature superconductivity in YH${}_6$
• Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
• Superconductivity at 161 K in Thorium Hydride $Th{H}_{10}$: Synthesis and Properties
• Superconductivity at 253 K in lanthanum-yttrium ternary hydrides
• High-Temperature Superconductivity in Cerium Superhydrides
• LaBH${}_8$: the first high-T${}_c$ low-pressure superhydride
• High-Temperature Superconductivity in Alkaline and Rare Earth Polyhydrides at High Pressure: A Theoretical Perspective
• Dissociation of high-pressure solid molecular hydrogen: Quantum Monte Carlo and anharmonic vibrational study
• Superconductivity of $La{H}_{10}$ and $La{H}_{16}$ polyhydrides
• Possible Superconductivity Approaching Ice Point
• Phonon-mediated high-temperature superconductivity in ternary borohydride KB${}_2$H${}_8$ around 12 GPa
• High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride
• $\text{Spglib}$: a software library for crystal symmetry search
• Origin of High-Temperature Superconductivity in Compressed LaH${}_{10}$
• How Compressed Hydrides Produce Room Temperature Superconductivity
• Superconductivity of platinum hydride
• Stabilization mechanism of clathrate H cages in a room-temperature superconductor LaH${}_{10}$
• Stability and superconductivity of lanthanum and yttrium decahydrides
• Prediction of an unusual trigonal phase of superconducting LaH${}_{10}$ stable from 250 to 425 GPa pressure

Cited by in corpus (1)

• Stability and distortion of fcc-LaH${}_{10}$ with path-integral molecular dynamics