Suppression of twinning and enhanced electronic anisotropy of SrIrO3 films

TL;DR

This study shows how substrate engineering can suppress twinning in SrIrO3 films, revealing enhanced electronic anisotropy and offering new ways to manipulate electronic transport for quantum device applications.

Contribution

The paper demonstrates a method to reduce twinning in SrIrO3 films on SrTiO3 substrates, enabling the study of intrinsic electronic anisotropy in strained thin films.

Findings

Twinning in SrIrO3 films can be suppressed on specific substrates.

Electronic anisotropy increases with film thickness and strain.

Substrate engineering allows manipulation of electronic transport properties.

Abstract

The spin-orbit coupling and electron correlation in perovskite SrIrO3 (SIO) strongly favor new quantum states and make SIO very attractive for next generation quantum information technology. In addition, the small electronic band-width offers the possibility to manipulate anisotropic electronic transport by strain. However, twinned film growth of SIO often masks electronic anisotropy which could be very useful for device applications. We demonstrate that the twinning of SIO films on (001) oriented SrTiO3 (STO) substrates can be strongly reduced for thin films with thickness t less than 30 nm by using substrates displaying a TiO2-terminated surface with step-edge alignment parallel to the a- or b-axis direction of the substrate. This allows us to study electronic anisotropy of strained SIO films which hitherto has been reported only for bulk-like SIO. For films with t < 30 nm electronic anisotropy increases with increasing t and becomes even twice as large compared to nearly strain-free films grown on (110) DyScO3. The experiments demonstrate the high sensitivity of electronic transport towards structural distortion and the possibility to manipulate transport by substrate engineering.