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

The high-pressure behavior of the orthorhombic cotunnite type ZrO 2 is explored using an ab initio constant pressure technique. For the first time, a novel hexagonal phase (Ni 2 In type) within P6 3 /mmc symmetry is predicted through the simulation. The Ni 2 In type crystal is the densest high-pressure phase of ZrO 2 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 380 GPa in experiment. [ABSTRACT FROM AUTHOR]