A new class of half-metallic ferromagnets from first principles

TL;DR

This paper uses first-principles calculations to understand and predict new half-metallic ferromagnets in the ThCr2Si2 structure, which are promising for spintronic applications due to their high Curie temperatures.

Contribution

It provides a theoretical understanding of HMFM in ThCr2Si2 compounds and predicts new materials with high Curie temperatures through alloying.

Findings

Identifies the conditions for half-metallicity in ThCr2Si2 compounds.

Explains the emergence of ferromagnetism at a quantum critical point.

Predicts new candidate materials with high Curie temperatures.

Abstract

Half-metallic ferromagnetism (HMFM) occurs rarely in materials and yet offers great potential for spintronic devices. Recent experiments suggest a class of compounds with the `ThCr$_{2}$Si$_{2}$' (122) structure -- isostructural and containing elements common with Fe pnictide-based superconductors -- can exhibit HMFM. Here we use $ab$ $initio$ density-functional theory calculations to understand the onset of half-metallicity in this family of materials and explain the appearance of ferromagnetism at a quantum critical point. We also predict new candidate materials with HMFM and high Curie temperatures through A-site alloying.