Novel high-pressure phase of ZrO2: An ab initio prediction

Abstract

The high-pressure behavior of the orthorhombic cotunnite type ZrO2 is explored using an ab initio constant pressure technique. For the first time, a novel hexagonal phase (Ni2In type) within P63/mmc symmetry is predicted through the simulation. The Ni2In type crystal is the densest high-pressure phase of ZrO2 proposed so far and has not been observed in other metal dioxides at high pressure before. The phase transformation is accompanied by a small volume drop and likely to occur around 380GPa in experiment.