Enhanced anomalous Hall conductivity via Ga doping in Mn\textsubscript{3}Sn and Mn\textsubscript{3}Ge

Abstract

This study examines the anomalous Hall effect (AHE) in the Heusler series \ce{Mn3Z} (Z=Ga, Ge, Sn), with a particular emphasis on the manipulation of non-collinear antiferromagnetic structures to enhance AHE. By employing density-functional theory and first-principles calculations, we demonstrate that the anomalous Hall conductivity is markedly responsive to electron filling. By strategically doping Ga into \ce{Mn3Sn} and \ce{Mn3Ge} in order to modulate the electron density, a significant increase in anomalous Hall conductivity (AHC) is achieved. It is noteworthy that a Ga:Sn ratio of 1:5 yields peak AHC values exceeding $\mathrm{700(\Omega \cdot cm)^{-1}}$, while 3:7 Ga-Ge ratios can result in AHC values surpassing $600\mathrm{(\Omega \cdot cm)^{-1}}$. A comparison between the virtual crystal approximation and supercell construction methods for doping has revealed consistent trends. The results of this study pave the way for optimizing AHE in non-collinear AFM materials.