Li2NiSe2: A new-type intrinsic two-dimensional ferromagnetic semiconductor above 200 K

Abstract

By using first-principles electronic structure calculations, we propose a two-dimensional ferromagnetic semiconductor Li2NiSe2 with a Curie temperature above 200 K. The structure of monolayer Li2NiSe2 is dynamically stable, which is derived from the synthesized prototype compound Li2NiO2 and can be denoted as Li-decorated 1T-type NiSe2. The Ni–Se–Ni ferromagnetic superexchange dominates the magnetic couplings between the Ni atoms, which can be understood in the frame of the Goodenough–Kanamori–Anderson (GKA) rules. Our systematic study of monolayer Li2NiSe2 enables its promising applications in spintronics and suggests a new choice to design two-dimensional ferromagnetic semiconductors.