Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity

TL;DR

This paper demonstrates a method to precisely control oxygen vacancy distribution in oxides using nanoscale flexoelectricity induced by a scanning probe, enabling new device functionalities.

Contribution

It introduces a novel approach to manipulate oxygen vacancies via nanoscale flexoelectric effects with a scanning probe, combining experimental imaging and simulations.

Findings

Oxygen vacancies can be moved under stress-gradient-induced depolarisation fields.

Nanoscale flexoelectricity enables deterministic spatial modulation of vacancies.

Controlled vacancy manipulation can be used for quantum phenomena exploration and device engineering.

Abstract

Oxygen vacancies, especially their distribution, are directly coupled to the electromagnetic properties of oxides and related emergent functionalities that have implication in device applications. Here using a homoepitaxial strontium titanate thin film, we demonstrate a controlled manipulation of the oxygen vacancy distribution using the mechanical force from a scanning probe microscope tip. By combining Kelvin probe force microscopy imaging and phase-field simulations, we show that oxygen vacancies can move under a stress-gradient-induced depolarisation field. When tailored, this nanoscale flexoelectric effect enables a controlled spatial modulation. In motion, the scanning probe tip thereby deterministically reconfigures the spatial distribution of vacancies. The ability to locally manipulate oxygen vacancies on-demand provides a tool for the exploration of mesoscale quantum phenomena, and engineering multifunctional oxide devices.