Dynamic Modulation of the Transport Properties of the LaAlO3/SrTiO3 Interface Using Uniaxial Strain

TL;DR

This study demonstrates dynamic uniaxial strain control of transport properties at the LaAlO3/SrTiO3 interface using a magnetostrictive template, revealing significant anisotropic conductivity modulation at low temperatures.

Contribution

It introduces a novel method for applying dynamic uniaxial strain to oxide heterostructures, enabling real-time control and investigation of strain effects on electronic transport.

Findings

Conductivity along the strained direction decreases by up to 70% under tensile strain.

Conductivity increases by 6.8% under compressive strain at 2 K.

Transport properties are anisotropically modulated depending on current direction.

Abstract

Among the interfacial transport modulations to the LaAlO3/SrTiO3 (LAO/STO) heterostructure, mechanical strain has been proven to be an effective approach by growing the LAO/STO films on different substrates with varying lattice mismatches to STO. However, this lattice-mismatch-induced strain effect is static and biaxial, hindering the study of the strain effect in a dynamic way. In this work we realize dynamic and uniaxial strain to the LAO/STO oxide heterostructure at low temperature, through mechanical coupling from a magnetostrictive template. This anisotropic strain results in symmetry breaking at the interface and induces further splitting of the electronic band structure and therefore produces different conductivities along the x and y in-plane directions. In particular, we observe that along the strained direction the interface conductivity decreases by up to 70% under a tensile strain, while it increases by 6.8% under a compressive strain at 2 K. Also, it is revealed that the modulation on the interfacial transport property can be anisotropic, i.e., the resistance changes differently when an excitation current is parallel or perpendicular to the strain direction. This approach of strain engineering provides another degree of freedom for control of transport properties of oxide heterostructures and opens an additional way to investigate strain effects in materials science.