Persistent semi-metal-like nature of epitaxial perovskite CaIrO3 thin films

TL;DR

This study demonstrates that epitaxial CaIrO3 thin films maintain semi-metal-like properties under various strain conditions, revealing insights into the physics of strong spin-orbit coupled 5d oxides.

Contribution

It reports the stabilization of high-quality epitaxial CaIrO3 films and shows their semi-metallic nature persists despite applied strain, highlighting robustness in their electronic properties.

Findings

Semi-metallic behavior remains under tensile and compressive strain.

Strain causes only minor changes in electronic bandwidth.

Magnetoresistance is positive with quadratic field dependence.

Abstract

Strong spin-orbit coupled 5d transition metal based ABO3 oxides, especially iridates, allow tuning parameters in the phase diagram and may demonstrate important functionalities, for example, by means of strain effects and symmetry-breaking, because of the interplay between the Coulomb interactions and strong spin-orbit coupling. Here, we have epitaxially stabilized high quality thin films of perovskite (Pv) CaIrO3. Film on the best lattice-matched substrate shows semi-metal-like characteristics. Intriguingly, imposing tensile or compressive strain on the film by altering the underlying lattice-mismatched substrates still maintains semi-metallicity with minute modification of the effective correlation as tensile (compressive) strain results in tiny increases (decreases) of the electronic bandwidth. In addition, magnetoresistance remains positive with a quadratic field dependence. This persistent semi-metal-like nature of Pv-CaIrO3 thin films with minute changes in the effective correlation by strain may provide new wisdom into strong spin-orbit coupled 5d based oxide physics.