Tuning electronic structures via epitaxial strain in Sr2IrO4 thin films

TL;DR

This study demonstrates how epitaxial strain in Sr2IrO4 thin films can modulate their electronic structures, revealing the interplay between lattice strain, electronic bandwidth, and correlation effects in spin-orbit coupled materials.

Contribution

It provides experimental evidence that epitaxial strain influences electronic correlations and optical properties in Sr2IrO4, offering new insights into strain-engineered quantum materials.

Findings

Optical absorption peaks shift with strain, indicating changes in electronic correlation.

Epitaxial strain affects Ir-O-Ir bond angles and electronic bandwidths.

Electronic structures can be tuned via lattice modifications in Sr2IrO4.

Abstract

We have synthesized epitaxial Sr2IrO4 thin-films on various substrates and studied their electronic structures as a function of lattice-strains. Under tensile (compressive) strains, increased (decreased) Ir-O-Ir bond-angles are expected to result in increased (decreased) electronic bandwidths. However, we have observed that the two optical absorption peaks near 0.5 eV and 1.0 eV are shifted to higher (lower) energies under tensile (compressive) strains, indicating that the electronic-correlation energy is also affected by in-plane lattice-strains. The effective tuning of electronic structures under lattice-modification provides an important insight into the physics driven by the coexisting strong spin-orbit coupling and electronic correlation.