Compressive strain-induced metal-insulator transition in orthorhombic SrIrO3 thin films

TL;DR

This study explores how compressive strain in orthorhombic SrIrO3 thin films induces a metal-insulator transition, revealing weak localization effects despite persistent metallic optical responses.

Contribution

It demonstrates strain-induced metal-insulator transition in SrIrO3 thin films and attributes it to weak localization, using comprehensive transport and optical measurements.

Findings

Resistivity increases with compressive strain

Metallic optical response persists despite insulating behavior

Negative magnetoresistance indicates weak localization

Abstract

We have investigated the electronic properties of epitaxial orthorhombic SrIrO3 thin-films under compressive strain. The metastable, orthorhombic SrIrO3 thin-films are synthesized on various substrates using an epi-stabilization technique. We have observed that as in-plane lattice compression is increased, the dc-resistivity (\r{ho}) of the thin films increases by a few orders of magnitude, and the d\r{ho}/dT changes from positive to negative values. However, optical absorption spectra show Drude-like, metallic responses without an optical gap opening for all compressively-strained thin films. Transport measurements under magnetic fields show negative magneto-resistance at low temperature for compressively-strained thin-films. Our results suggest that weak localization is responsible for the strain-induced metal-insulator transition for the orthorhombic SrIrO3 thin-films.