Hole doping induced ferromagnetism and Dzyaloshinskii–Moriya interaction in the two-dimensional group-IVA oxides

Abstract

Based on the first-principles calculations, we examine the effect of hole doping on the ferromagnetism and Dzyaloshinskii–Moriya interaction (DMI) for PbSnO2, SnO2 and GeO2 monolayers. The nonmagnetic to ferromagnetic transition and the DMI can emerge simultaneously in the three two-dimensional IVA oxides. By increasing the hole doping concentration, we find the ferromagnetism can be strengthened for the three oxides. Due to different inversion symmetry breaking, isotropic DMI is found in PbSnO2, whereas anisotropic DMI presents in SnO2 and GeO2. More appealingly, for PbSnO2 with different hole concentrations, DMI can induce a variety of topological spin textures. Interestingly, a peculiar feature of synchronously switch of magnetic easy axis and DMI chirality upon hole doping is found in PbSnO2. Hence, Néel-type skyrmions can be tailored via changing hole density in PbSnO2. Furthermore, we demonstrate that both SnO2 and GeO2.with different hole concentrations can host antiskyrmions or antibimerons (in-plane antiskyrmions). Our findings demonstrate the presence and tunability of topological chiral structures in p-type magnets and open up new possibility for spintronics.