Switchable polarization in non-ferroelectric SrTiO$_3$

TL;DR

This study demonstrates that intrinsic defects can induce and switch polarization in non-ferroelectric SrTiO$_3$, revealing potential for defect-engineered functionalities in perovskite materials.

Contribution

It shows that defect engineering can create and control switchable polarization in SrTiO$_3$, a non-ferroelectric perovskite, using density-functional theory.

Findings

Defects induce strong spontaneous polarization in SrTiO$_3$.

Polarization can be switched by defect site symmetry.

Switching alters the spatial distribution of defect states.

Abstract

Perovskites with tunable and switchable polarization hold immense promise for unlocking novel functionalities. Using density-functional theory, we reveal that intrinsic defects can induce, enhance, and control polarization in non-ferroelectric perovskites, with SrTiO$_3$ as our model system. At high defect concentrations, these systems exhibit strong spontaneous polarization - comparable to that of conventional ferroelectrics. Crucially, this polarization is switchable, enabled by the inherent symmetry-equivalence of defect sites in SrTiO$_3$. Strikingly, polarization switching not only reverses the polarization direction and modulates its magnitude but also modifies the spatial distribution of localized defect states. This dynamic behavior points to unprecedented responses to external stimuli, opening new avenues for defect-engineered materials design.