The nature of deformation-induced dislocations in SrTiO3: Insights from atomistic simulations

TL;DR

This study uses atomistic simulations to analyze the structure and mobility of dislocations in SrTiO3, revealing how different dislocation types and charge states influence their movement and material ductility.

Contribution

It provides a systematic computational analysis of dislocation structures and mobility in SrTiO3, focusing on the effects of partial dislocation splitting and charge states.

Findings

Dislocations on {1-10} glide planes show easy glide behavior.

Dislocations on {001} and {1-1-2} glide planes are hindered by high Peierls barriers.

Charge state affects dislocation dissociation and potentially macroscopic ductility.

Abstract

The nature of mechanically induced dislocations in SrTiO3 at low temperatures has been a disputed matter for a long time. Here we provide a systematic overview of the existing knowledge on dislocations in stoichiometric SrTiO3 complemented by computational models of several of the proposed dislocation types. Based on atomistic simulations we reveal their structure and mobility and put our focus on the splitting into partial dislocations, because this mechanism is held responsible for the good dislocation mobility in strontium titanate. Our results reveal that dislocations with a {1-10} glide plane (types A, B, and C) show easy glide behavior due to their glide dissociated configuration. The motion of dislocations on {001} glide planes (type E), however, is prohibited due to high Peierls barriers, as is the case for the {1-1-2} glide plane (type D). For dislocations with (partial) edge character the dissociation into partials is shown to be very sensitive to the charge state of the dislocation core. Since, in turn, dislocation mobility is strongly related to the dissociation of dislocations, the macroscopic ductility may in some cases have a direct relation to the charge at the dislocation core.