1T GdN2 monolayer — Spin-orbit induced magnetic Dirac semiconductor stable at room temperature

Abstract

Room-temperature magnetic semiconductor has been regarded as essential material for emerging spintronic devices. In recent years, two-dimensional ferromagnetism is even of great interest to explore basic physics in spintronics. Here, we report on 1T GdN2 monolayer as a promising p-state magnetic Dirac semiconductor. We uncover the mechanism of band shift induced by the exchange of Gd 4f7 half-full shell and the origin of N 2p Dirac bands with unique spin. By virtue of localized rare-earth 4f electrons, strong exchange plays a role in modifying the order of bands. Spin-orbit coupling opens a gap between two Dirac bands with SU(2) spin symmetry breaking and makes 1T GdN2 a relativistic magnetic semiconductor. High Curie temperature and large magnetic anisotropy energy give 1T GdN2 prominent merit to be an ideal spintronic material.