First-principles studies on the magnetic properties, exchange interactions and spin Hall conductivity of the half-Heusler alloy MgMnGe

Abstract

This study presents first-principles estimates of the magnetic characteristics, exchange interactions and the spin Hall conductivity (SHC) of the half -Heusler alloy MgMnGe. Various configurations of spin-ordering are taken into consideration. It is discovered that MgMnGe has an antiferromagnetic ground state, with a degenerate in plane Néel vector. The Korringa-Kohn-Rostoker method has been used to calculate the Néel temperature and exchange interactions. The Néel temperature of this material obtained theoretically using mean field approximation is 447.2 K while the experimental reported value is largely higher than 300 K. The exchange interaction has been shown to be mostly mediated by the Mn1-Mn2 exchange. The spin Hall conductivity of MgMnGe is obtained by mapping the electronic structures to the Wannier basis via linear response theory. The spin Hall conductivity as a function of the Fermi level has been determined.