Doping-induced ferromagnetism in InSe and SnO monolayers

Abstract

Hole-doping of GaX, InX (X = S or Se) and SnO monolayers is predicted to induce a stable ferromagnetic order in these two-dimensional materials, making them potentially interesting for nanoscaled spintronic devices. Ferromagnetism in these materials arises from their peculiar Mexican-hat valence band edge structure, which leads to a Stoner instability. We discuss here the results from first-principles simulations on the p-type doping-induced ferromagnetism in these 2D materials. Hole-doping, induced by intrinsic and extrinsic point defects, is considered. Metal vacancies are found to produce shallow spin-polarized gap states near the valence band edge, leading to a p-type behavior. Among the investigated potential extrinsic defects (dopants), As substitution of the oxygen atoms in SnO or Bi substitution of the selenium atoms in InSe appears to be good candidates for the hole-doping of these 2D materials.