High entropy alloy superconductors -- status, opportunities and challenges

TL;DR

This paper reviews the current state, key factors, and future opportunities in high entropy alloy superconductors, highlighting their unique properties and the challenges in discovering new materials.

Contribution

It provides a comprehensive update on superconducting HEAs, summarizing progress, influencing factors, and outlining future research directions and challenges.

Findings

Superconducting HEAs are influenced by crystal structure and atomic composition.

Current research is limited mostly to 4d metal-based HEAs.

Opportunities exist for discovering new HEA superconductors.

Abstract

High entropy alloys (HEAs) are a recently-opened research area in materials science and condensed matter physics. Although 3d-metal-based HEAs have already been the subject of many investigations, studies of HEA superconductors, which tend to be based on 4d metals, are relatively fewer. Here we provide a short update of the progress made in studies of superconducting HEAs. We aim to summarize their current status and describe some of the key factors that appear to influence their superconducting transition temperatures and properties, including crystal structure, atomic makeup, valence electron count, molar volume and mixing entropy. Many opportunities and challenges remain for expanding our knowledge of HEA superconductors, finding new types of HEA superconductors, and their potential for applications; these are also briefly discussed.