Prediction of Room-Temperature Ferromagnetism in a Two-dimensional Direct Band Gap Semiconductor
Two-dimensional (2D) ferromagnetic (FM) semiconductors with direct electric band gap have recently drawn much attention due to their promising potential for spintronic and magneto-optical applications. However, the Curie temperatures (TC) of recent synthesized 2D FM semiconductors are too low (~45 K) and a room-temperature 2D direct band gap FM semiconductor has never been reported, which hinders the development for practical applications. Here, we show that through isovalent alloying, one can increase the TC of a 2D FM semiconductor up to room temperature and simultaneously turn it from an indirect to a direct band gap semiconductor. Using first-principles calculations, we predict that the alloyed CrMoS2Br2 monolayer is a direct band gap semiconductor with TC of ~360 K, whereas the pristine CrSBr monolayer is an indirect band gap semiconductor with TC of ~180 K. These findings provide a promising pathway to realize 2D direct band gap FM semiconductors with TC above room temperature, which will greatly stimulate theoretical and experimental interest in future spintronic and magneto-optical applications.
- This article is part of the themed collection: 2020 Nanoscale HOT Article Collection