Reversible Electric Field-Induced Structure Changes in the Near-Surface Region of Strontium Titanate

Abstract

X-ray analysis of the near-surface region of as-cut single-crystalline strontium titanate (001) wafers showed a reversible electric field-induced structure change at room temperature. To explain this phenomenon, a model is proposed which is based on the field-driven diffusional transport of oxygen and strontium along dislocation cores to the near-surface region and the growth of monolayer SrO precipitates by dislocation climb. Precipitate growth causes a lateral compressive stress in the near-surface region, which counteracts the diffusion of oxygen and strontium to the surface. By estimating the change of the Gibbs free energy due to precipitate formation, the lateral precipitate size and the resulting mean strain in the near-surface region is analyzed.