Stability of Polar Structure in Filling-Controlled Giant Tetragonal Perovskite Oxide PbVO.

The crystal structure and stability of a giant tetragonal phase in electron-doped PbBi VO ( x = 0.1, 0.2, and 0.3) and hole-doped PbNa VO ( x = 0.1, 0.2, and 0.3) were studied. Electron doping effectively destabilized the tetragonal structure. The c/ a ratio, spontaneous polarization, and tetragonal-to-cubic phase transition pressure systematically decreased with increasing Bi substitution. In contrast, hole doping hardly affected the tetragonal distortion and structural stability. We showed that electron doping is an effective way to control the stability of the tetragonal phase of PbVO with a 3d electronic configuration.