Influence of defects on the electronic and magnetic properties of half-metallic CrAs, CrSe and CrSb zinc-blende compounds

TL;DR

This study investigates how various defects affect the electronic and magnetic properties of half-metallic Cr-based zinc-blende compounds, revealing that most defects introduce states within the gap that can compromise half-metallicity.

Contribution

It provides a detailed analysis of impurity effects on CrAs, CrSb, and CrSe compounds, highlighting how defects influence their half-metallic behavior and electronic structure.

Findings

Most defects induce in-gap states affecting half-metallicity

Void impurities at certain sites and some impurities do not create in-gap states

Impurity interactions can lead to loss of half-metallic character

Abstract

We present an extended study of single impurity atoms and atomic swaps in half-metallic CrAs, CrSb and CrSe zinc-blende compounds. Although the perfect alloys present a rather large gap in the minority-spin band, all defects under study, with the exception of void impurities at Cr and sp sites and Cr impurities at sp sites (as long as no swap occurs), induce new states within the gap. The Fermi level can be pinned within these new minority states depending on the lattice constant used for the calculations and the electronegativity of the sp atoms. Although these impurity states are localized in space around the impurity atoms and very fast we regain the bulk behavior, their interaction can lead to wide bands within the gap and thus loss of the half-metallic character.