First-principles thermal equation of state of fcc iridium

Abstract

The thermal equation of states for fcc iridium (Ir) is obtained from first-principles molecular dynamics up to 3000 K and 540 GPa. The equation of state (EoS) is globally fitted to a simplified free energy model and various parameters are derived. The theoretical principal Hugoniot is compared with shockwave experiments, where discrepancy suggests formation of new Ir phases. A few representative EoS parameters, such as bulk modulus $K_T$, thermal expansivity $\alpha$, Grüneisen parameter $\gamma$, and constant pressure capacity $C_P$, Debye temperature, ${\Theta }_D$ are computed to compare with experimental data

10 pages, 12 figures

References in corpus (2)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Canonical sampling through velocity-rescaling

Cited by in corpus (1)

• Ab initio thermodynamic properties of Iridium: A high-pressure and high-temperature study