Disorder by Design: Unveiling Local Structure and Functional Insights in High Entropy Oxides

TL;DR

This paper reviews how local structural and chemical disorder in high entropy oxides influences their functional properties, emphasizing recent experimental and theoretical advances for rational material design.

Contribution

It provides a comprehensive framework linking local disorder to functional properties in high entropy oxides, integrating experimental and theoretical insights.

Findings

Local disorder affects ionic transport and redox behavior.

Advanced spectroscopy reveals multi-scale structural insights.

Framework connects disorder to emergent functionalities.

Abstract

High entropy oxides (HEOs) are a rapidly growing class of compositionally complex ceramics in which configurational disorder is engineered to unlock novel functionality. While average crystallographic symmetry is often retained, local structural and chemical disorder, including cation size and valence mismatch, oxygen sublattice distortions, and site-specific bonding, strongly governs ionic transport, redox behavior, magnetic ordering, and dielectric response. This review outlines how these modes of disorder manifest across key oxide families such as rock salt, spinel, fluorite, and perovskite. We highlight recent advances in spectroscopy, total scattering, and high-resolution microscopy enable multi-scale insight into short- and intermediate-range order. By integrating experimental observations with theoretical modeling of entropy and local energetics, we establish a framework linking structural heterogeneity to emergent properties. These insights not only deepen our fundamental understanding of disorder-property relationships but also offer a path toward rational design of tunable materials for catalysis, energy storage, electronics, and much more.