By classical and path-integral molecular dynamics simulations, we study the pressure-temperature (P-T) phase diagram of LaH10 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 ≤P≤ 150 GPa and T=300 K, we show that a highly symmetric Fm3ˉm 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 Fm3ˉm 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 Fm3ˉm structure and those with lower symmetries.
@article{arxiv.2205.06524,
title = {Quantum and temperature effects on crystal structure of superhydride: A path integral molecular dynamics study},
author = {Yuta Watanabe and Takuya Nomoto and Ryotaro Arita},
journal= {arXiv preprint arXiv:2205.06524},
year = {2022}
}