Anisotropic electronic properties of a-axis-oriented Sr2IrO4 epitaxial thin-films

TL;DR

This study explores the anisotropic electronic and optical properties of a-axis-oriented Sr2IrO4 epitaxial thin-films, revealing significant differences along different crystallographic axes and the impact of strain on electronic structure.

Contribution

It provides new insights into the anisotropic transport and optical behaviors of Sr2IrO4 thin-films and demonstrates their potential for studying directional electronic properties.

Findings

c-axis resistivity is ten times larger than ab-plane resistivity

Optical spectra show different transitions depending on polarization

Strain alters electronic structure and gap energy

Abstract

We have investigated the transport and optical properties along the c-axis of a-axis-oriented Sr2IrO4 epitaxial thin-films grown on LaSrGaO4 (100) substrates. The c-axis resistivity is approximately one order of magnitude larger than that of the ab-plane. Optical absorption spectra with E//b polarization show both Ir 5d intersite transitions and charge-transfer transitions (O 2p to Ir 5d), while E//c spectra show only the latter. The structural anisotropy created by biaxial strain in a-axis-oriented thin-films also changes the electronic structure and gap energy. These a-axis-oriented, epitaxial thin-films provide a powerful tool to investigate the highly anisotropic electronic properties of Sr2IrO4.