Pressure-Induced Anomalous Phase Transitions and Colossal Enhancements of Piezoelectricity in Ground-State BaTiO ₃

Abstract

Rhombohedral BaTiO3 under hydrostatic pressure is investigated by first principles calculations. Our results show that just like tetragonal perovskites, as pressure increases, this material first becomes para-electric at low pressures, then transfers to another ferroelectric phase at much higher pressures. We also find a giant enhancement of piezoelectricity near the phase-transition regions, due to large atomic displacements along different directions in response to the applied pressures.

Dynamic Investigations of Pressure-Induced Abnormal Phase Transitions in PbTiO 3

“…[1−5] The essential features of these materials, spontaneous polarization and piezoelectricity, are closely related to the structures belonging to the noncentrosymmetric subgroups and are sensitive to external conditions, such as strain, temperature, and pressure. [6,7] Ferroelectricity occurs at noncentrosymmetric phases, usually tetragonal and rhombohedral, for perovskite oxides. PbTiO 3 , a symbolic member of FE materials, has been under intensive study, [8−11] which is crucial to understand the giant piezoelectric responses of relaxor-PTO materials, such as PbZn 1/3 Nb 2/3 O 3 -PbTiO 3 and Pb(Mg 1/3 Nb 2/3 O 3 )-PbTiO 3 .…”