The high-pressure stability of Ni2In-type structure of ZrO2 with respect to OII and Fe2P-type phases: A first-principles study

摘要

The density-functional theory is used to investigate the stability of the Ni2In-type hexagonal structure with the space group: P63/mmc at high pressures and compared to the orthorhombic OII and Fe2P-type phases of zirconia (ZrO2). The calculations showed that the high-pressure phase transition sequence in ZrO2 is as follows: OII →Fe2P →Ni2In, which is consistent with the recent measurements that are observed in Fe2P as a post-OII phase of ZrO2. We obtained a very small volume change across OII → Fe2P transition, whereas an appreciable volume change is found across the Fe2P→Ni2In transition. The compressibility of Ni2In phase is found to be high as compared to the other two high-pressure phases.