Antiferromagnetism, spin splitting, and spin-orbit interaction in MnTe

TL;DR

This study uses ab initio density functional theory to explore the magnetic, electronic, and spin properties of hexagonal MnTe, revealing antiferromagnetic order, spin splitting, and ferroelectricity, aiding heterostructure design.

Contribution

It provides a detailed first-principles analysis of MnTe's magnetic and spin-orbit properties, including the discovery of combined Rashba-Dresselhaus interactions and ferroelectricity.

Findings

MnTe exhibits antiferromagnetic insulating state.

Large spin splitting due to antiferromagnetic order without spin-orbit coupling.

Identification of Rashba-Dresselhaus spin-orbit interaction in the system.

Abstract

Hexagonal MnTe emerges as a critical component in designing magnetic quantum heterostructures, calling for a detailed study. After finding a suitable combination of exchange-correlation functional and corrections, our study within {\em ab initio} density functional theory uncovers an insulating state with a preferred antiferromagnetic order. We compute the exchange interaction strengths to estimate the antiferromagnetic ordering temperature via Monte Carlo calculations. Our calculations and symmetry analysis reveal a large spin splitting in the system due to the antiferromagnetic order without considering spin-orbit interaction, except in the $k_x$-$k_y$ plane. Critically examining the band dispersion and spin textures obtained from our calculations and comparing them with an insightful symmetry analysis and analytical model, we confirm a combined Rashba-Dresselhaus interaction in the $k_x$-$k_y$ plane, around the K point of the system. Finally, we find ferroelectricity in the system for a higher energy magnetic configuration. Our results and insights would help design heterostructures of MnTe for technological applications.