Pressure-Induced Simultaneous Metal-Insulator and Structural-Phase Transitions in LiH: a Quasiparticle Study

TL;DR

This study predicts a pressure-induced simultaneous metal-insulator and structural phase transition in lithium hydride using advanced quasiparticle calculations, highlighting the importance of accurate approximations for predicting material behavior under pressure.

Contribution

It demonstrates that combining the generalized-gradient approximation with zero-point vibrations yields accurate predictions of lithium hydride's properties and correctly models the simultaneous phase transition.

Findings

Predicted a 1% volume collapse during phase transition

LDA incorrectly predicts the sequence of transitions

GGA with zero-point vibrations matches experimental data

Abstract

A pressure-induced simultaneous metal-insulator transition (MIT) and structural-phase transformation in lithium hydride with about 1% volume collapse has been predicted by means of the local density approximation (LDA) in conjunction with an all-electron GW approximation method. The LDA wrongly predicts that the MIT occurs before the structural phase transition. As a byproduct, it is shown that only the use of the generalized-gradient approximation together with the zero-point vibration produces an equilibrium lattice parameter, bulk modulus, and an equation of state that are in excellent agreement with experimental results.