Tuning oxygen vacancy diffusion through strain in SrTiO$_3$ thin films

TL;DR

This study investigates how external strain influences oxygen vacancy diffusion in SrTiO$_3$ thin films, revealing that tensile strain significantly enhances vacancy mobility, which is vital for designing ion-based electronic and memristive devices.

Contribution

It provides the first quantitative analysis of how epitaxial strain affects oxygen vacancy diffusion coefficients in SrTiO$_3$ thin films at room temperature.

Findings

Tensile strain increases oxygen vacancy diffusion coefficient.

Tip bias, pulse duration, and temperature affect vacancy concentration.

Strain plays a key role in controlling vacancy migration.

Abstract

Understanding the diffusion of oxygen vacancies in oxides under different external stimuli is crucial for the design of ion-based electronic devices, improve catalytic performance, etc. In this manuscript, using an external electric field produced by an AFM tip, we obtain the room-temperature diffusion coefficient of oxygen-vacancies in thin-films of SrTiO$_3$ under compressive/tensile epitaxial strain. Tensile strain produces a substantial increase of the diffusion coefficient, facilitating the mobility of vacancies through the film. Additionally, the effect of tip bias, pulse time, and temperature on the local concentration of vacancies is investigated. These are important parameters of control in the production and stabilization of non-volatile states in ion-based memresistive devices. Our findings show the key role played by strain for the control of oxygen vacancy migration in thin-film oxides.