Spin magnetization of magnetic topological surface states in the presence of band asymmetry

Abstract

In this work we investigate spin magnetization of surface electrons in magnetic topological insulators in the presence of electron–hole band asymmetry. The asymmetry is introduced by quadratic momentum term. The asymmetry in LL spectrum and unique zeroth LL behavior leads to unusual behavior of electron spin magnetization. Electronic magnetization behavior changes from positive to negative depending on zeroth Landau level being electron-like or hole-like. We show that the critical magnetic field at which discontinuity occurs depends both on intrinsic magnetic gap Δ0 and mass term. We show that plateau structure in magnetization depends on interplay of linear and quadratic momentum terms in electronic dispersion as chemical potential is tuned. It is also observed that the plateau structure in our system is unlike conventional oscillatory behavior in 2DEG or plateaus in particle hole symmetric surface states in the absence of mass term.