Electronic and crystal structures of osmium under high pressure

Abstract

The equation of states, electronic and phonon band structure, Fermi surface, and transport properties of Os under high pressure have been studied with first-principles calculations. The theoretical results reproduced the experimentally observed anomaly in the $c∕a$ ratio around $25\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. Analysis of the electronic band structure and Fermi surface does not support an electronic topological transition. Moreover, no phonon softening was observed in the lattice dynamics calculations. However, calculations of the Hall coefficient reveal subtle changes in the electron band dispersions at the Fermi surface which may account for the observed anomaly in the $c∕a$ ratio.