Lattice dynamics and thermodynamics of bcc vanadium at high pressures

TL;DR

This study uses first-principles calculations to analyze the lattice dynamics and thermodynamic properties of bcc vanadium under high pressure and temperature, revealing temperature-dependent phonon behavior and providing detailed equation of state data.

Contribution

It offers new insights into the temperature dependence of phonon density of states and thermodynamic properties of bcc vanadium using first-principles methods, contrasting with experimental observations.

Findings

Phonon density of states shows strong temperature dependence.

Calculated thermodynamic properties agree with experimental data.

Discrepancies observed between calculated and measured phonon DOS at high temperatures.

Abstract

We investigate the lattice dynamics and thermodynamics of nonmagnetic bcc vanadium as a function of temperature and pressure, using the first principles linear response linear-muffin-tin-orbital method. The calculated phonon density of states (DOS) show strong temperature dependence, different from inelastic neutron scattering measurements where the phonon DOS show little change from room temperature up to 1273 K. We obtain the Helmholtz free energy including both electronic and phonon contributions and calculate various equation of state properties such as the bulk modulus and the thermal expansion coefficient. A detailed comparison has been made with available experimental measurements.