Ab initio study of stress-induced domain switching in PbTiO3

Abstract

We investigated the atomistic and electronic structure of the 90° domain wall in PbTiO3 and the fundamental mechanism of domain switching induced by shear stress using first-principles density functional theory calculations within the local density approximation. Under strain-free condition, the magnitude of polarization at the center of the domain wall decreased by 20% from that of the bulk, and the direction rotated within the transition region of 1.3 nm. Under strain, the applied shear deformation concentrated near the 90° domain wall, and the domain wall began to migrate in a direction perpendicular to itself after the stress reached the critical magnitude of 152 MPa. The migration direction was governed by the shearing direction. During stress-induced domain switching, a Pb-O covalent bond at the center of the domain wall broke, and concurrently, another bond on the neighboring Pb-O site was formed with a large movement of the Pb atom. Thus, reconstruction of the Pb-O bond was associated with the domain switching.