Chemically-Disordered Transparent Conductive Perovskites with High Crystalline Fidelity

TL;DR

This paper introduces a model linking chemical disorder to transport properties in high-entropy perovskites, demonstrating epitaxial Sr$x$(Ti,Cr,Nb,Mo,W)O$3$ films with exceptional properties for advanced electronic applications.

Contribution

It provides a new framework for designing chemically disordered perovskites with high crystalline fidelity and desirable electronic and optical properties, supported by experimental and computational analysis.

Findings

Epitaxial films exhibit high crystalline quality despite chemical disorder.

Disordered perovskites show low resistivity and broad optical transparency.

Predictive modeling enables expanded property design space for advanced devices.

Abstract

This manuscript presents a working model linking chemical disorder and transport properties in correlated-electron perovskites with high-entropy formulations and a framework to actively design them. We demonstrate this new learning in epitaxial Sr$x$(Ti,Cr,Nb,Mo,W)O$3$ thin films that exhibit exceptional crystalline fidelity despite a diverse chemical formulation where most B-site species are highly misfit with respect to valence and radius. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy confirm a unique combination of chemical disorder and structural perfection in thick epitaxial layers. This combination produces significant electron correlation, low electrical resistivity, and an optical transparency window that surpasses that of constituent end-members, with a flattened frequency- and temperature-dependent response. We address the computational challenges of modeling such systems and investigate short-range ordering using cluster expansion. These results showcase that unusual d-metal combinations access an expanded property design space that is predictable using end-member characteristics -- though unavailable to them -- thus offering performance advances in optical, spintronic, and quantum devices.