Structural phases arising from reconstructive and isostructural transitions in high-melting-point oxides under hydrostatic pressure: A first-principles study

作     者：Hao Tian Xiao-Yu Kuang Ai-Jie Mao Yurong Yang Changsong Xu S. Omid Sayedaghaee L. Bellaiche 

作者机构：Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China Physics Department and Institute for Nanoscience and Engineering University of Arkansas Fayetteville Arkansas 72701 USA Microelectronics-Photonics Program and Physics Department University of Arkansas Fayetteville Arkansas 72701 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第97卷第2期

页      面：020103(R)-020103(R)页

核心收录：

基　　金：100000015, (11574220) State Scholarship Fund Office of Naval Research, (10.13039/100000006 N00014-12-1-1034 N00014-17-1-2818) U.S. Department of Energy Defense Advanced Research Projects Agency Basic Energy Sciences National Natural Science Foundation of China, (10.13039/501100001809 11574220) China Scholarship Council 

主　　题：Phase transitions Pressure effects Crystal structures Oxides Perovskites First-principles calculations High-throughput calculations 

摘      要：High-melting-point oxides of chemical formula ABO3 with A=Ca, Sr, Ba and B=Zr, Hf are investigated as a function of hydrostatic pressure up to 200 GPa by combining first-principles calculations with a particle swarm optimization method. Ca- and Sr-based systems: (1) first undergo a reconstructive phase transition from a perovskite state to a novel structure that belongs to the post-post-perovskite family and (2) then experience an isostructural transition to a second, also new post-post-perovskite state at higher pressures, via the sudden formation of a specific out-of-plane B−O bond. In contrast, the studied Ba compounds evolve from a perovskite phase to a third novel post-post-perovskite structure via another reconstructive phase transition. The original characteristics of these three different post-post-perovskite states are emphasized. Unusual electronic properties, including significant piezochromic effects and an insulator-metal transition, are also reported and explained.