Equation of state of hexagonal-close-packed rhenium in the terapascal regime

Abstract

All-electron density functional theory calculations were performed aiming to determine the equation of state and the dependence with pressure of the $c/a$ ratio and the anisotropic compressibility for hexagonal-close-packed rhenium. Calculations were carried out up to maximum compression of 0.46, and the resulting total energy versus volume is well described by a Vinet equation of state with ${B}_{0}$ = 367(5) GPa and ${B}_{0}^{\ensuremath{'}}$ = 4.64(3), valid up to 1.5 TPa. The agreement with two recent experimental studies [S. Anzellini et al., Equation of state of rhenium and application for ultra high pressure calibration, J. Appl. Phys. 115, 043511 (2014); T. Sakai et al., High pressure generation using double-stage diamond anvil technique: Problems and equations of state of rhenium, High Pressure Res. 38, 107 (2018)] supports their conclusion that the pressure in previous experiments with a double-stage diamond-anvil cell [L. Dubrovinsky et al., Implementation of micro-ball nanodiamond anvils for high-pressure studies above 6 Mbar, Nat. Commun. 3, 1163 (2012)] was significantly overestimated.