Low-Temperature Dielectric Anisotropy Driven by an Antiferroelectric Mode in SrTiO_{3}.

Strontium titanate (SrTiO_{3}) is the quintessential material for oxide electronics. One of its hallmark features is the transition, driven by antiferrodistortive (AFD) lattice modes, from a cubic to a ferroelastic low-temperature phase. Here we investigate the evolution of the ferroelastic twin walls upon application of an electric field.

Erratum: Macroscopic Polarization from Antiferrodistortive Cycloids in Ferroelastic SrTiO_{3} [Phys. Rev. Lett. 119, 137601 (2017)].

This corrects the article DOI: 10.1103/PhysRevLett.119.

Macroscopic Polarization from Antiferrodistortive Cycloids in Ferroelastic SrTiO_{3}.

Based on a first-principles based multiscale approach, we study the polarity P of ferroelastic twin walls in SrTiO_{3}. In addition to flexoelectricity, which was pointed out before, we identify two new mechanisms that crucially contribute to P: a direct "rotopolar" coupling to the gradients of the antiferrodistortive oxygen tilts, and a trilinear coupling that is mediated by the antiferroelectric displacement of the Ti atoms. Remarkably, the rotopolar coupling presents a strong analogy to the mechanism that generates a spontaneous polarization in cycloidal magnets.