Elasticity of Diamond at High Pressures and Temperatures

TL;DR

This study uses advanced computational methods to accurately predict the elastic properties of diamond under extreme pressures and temperatures, validating the approach with experimental data and revealing increased anisotropy at high pressures.

Contribution

It introduces a first-principles computational approach combining density functional theory and vibrational analysis to predict diamond's elastic properties at high P-T conditions.

Findings

Excellent agreement with experimental data at ambient conditions

Anisotropy factor increases by 40% at high pressures

Elastic moduli are accurately predicted across P-T ranges

Abstract

We combine density functional theory within the local density approximation, the quasiharmonic approximation, and vibrational density of states to calculate single crystal elastic constants, and bulk and shear moduli of diamond at simultaneous high pressures and temperatures in the ranges of 0-500 GPa and 0-4800 K. Comparison with experimental values at ambient pressure and high temperature shows an excellent agreement for the first time with our first-principles results validating our method. We show that the anisotropy factor of diamond increases to 40% at high pressures and becomes temperature independent.