Determinants of local chemical environments and magnetic moments of high-entropy alloys

TL;DR

This study identifies key electronic descriptors that explain the local chemical environments and magnetic moments in high-entropy alloys, aiding the design of advanced structural materials.

Contribution

It introduces the use of cohesive energy and band filling from tight-binding and Friedel models to quantify chemical bonding and magnetic effects in HEAs, revealing their unique behaviors.

Findings

s-state cohesive energy determines bonding strength in CrMnFeCoNi

s-band filling correlates with magnetic moments in HEAs

Cr atoms exhibit localized and transferred itinerant electrons influencing properties

Abstract

High-entropy alloys (HEAs) such as CrMnFeCoNi exhibit unconventional mechanical properties due to their compositional disorder. However, it remains a formidable challenge to estimate the local chemical-environment and magnetic effects of HEAs. Herein we identify the state-associated cohesive energy and band filling originated from the tight-binding and Friedel models as descriptors to quantify the site-to-site chemical bonding and magnetic moments of HEAs. We find that the s-state cohesive energy is indispensable in determining the bonding-strength trend of CrMnFeCoNi that differs from the bonding characteristics of precious and refractory HEAs, while the s-band filling is effective in determining the magnetic moments. This unusual behavior stems from the unique chemical and magnetic nature of Cr atoms and is essentially due to the localized and transferred itinerant electrons. Our study establishes a fundamental physical picture of chemical bonding and magnetic interactions of HEAs and provides a rational guidance for designing advanced structural alloys.