Understanding the role of entropy in high entropy oxides

TL;DR

This paper explores how configurational entropy influences the stability and properties of high entropy oxides, aiming to guide the rational design of new materials with enhanced functionalities.

Contribution

It provides a framework for understanding the role of entropy in stabilizing phases and improving properties in high entropy oxides, addressing gaps in current characterization efforts.

Findings

Configurational disorder can lead to superior functional properties.

Entropy plays a key role in phase stabilization of HEOs.

A framework for analyzing entropy's impact in HEOs is proposed.

Abstract

The field of high entropy oxides (HEOs) flips traditional materials science paradigms on their head by seeking to understand what properties arise in the presence of profound configurational disorder. This disorder, which originates from multiple elements sharing a single lattice site, can take on a kaleidoscopic character due to the vast numbers of possible elemental combinations. High configurational disorder appears to imbue some HEOs with functional properties that far surpass their non-disordered analogs. While experimental discoveries abound, efforts to characterize the true magnitude of the configurational entropy and understand its role in stabilizing new phases and generating superior functional properties have lagged behind. Understanding the role of configurational disorder in existing HEOs is the crucial link to unlocking the rational design of new HEOs with targeted properties. In this Perspective, we attempt to establish a framework for articulating and beginning to address these questions in pursuit of a deeper understanding of the true role of entropy in HEOs.