Microscopic Origin of Piezomagnetism in Mn$_3$Sn: A Dual Real- and $k$-Space Picture

TL;DR

This study uses first-principles calculations to uncover how strain induces magnetization in Mn$_3$Sn by analyzing real-space magnetic moment rotations and Fermi surface changes in momentum space.

Contribution

It provides a dual real- and k-space explanation for the microscopic origin of piezomagnetism in Mn$_3$Sn, linking electronic structure and magnetic moment rotations.

Findings

Piezomagnetism arises from magnetic moment rotations at specific Mn sites.

Strain causes pseudo-degeneracy lifting on Fermi surfaces, inducing net magnetization.

Dual-space analysis offers deep insight into strain-driven magnetization mechanisms.

Abstract

We present a comprehensive first-principles study on the origin of the piezomagnetic effect in the non-collinear antiferromagnet Mn$_3$Sn, a material known for exhibiting a large anomalous Hall effect. We investigate strain-induced variations of electronic and magnetic states and elucidate the mechanism of the piezomagnetic effect from both real-space and momentum-space perspectives. In real space, the emergence of piezomagnetism is understood to arise from rotations of the magnetic moments at specific Mn sites, which directly couple to the strain. Through detailed electronic structure analysis, we identify the Fermi surfaces that play a crucial role in the emergence of piezomagnetism. Our results reveal that specific Fermi surface features undergo pseudo-degeneracy lifting under applied strain, which significantly contributes to the induced net magnetization. By combining these complementary real-space and momentum-space pictures, our dual-space analysis provides deep insight into the microscopic origins of strain-driven magnetization in Mn$_3$Sn.