Ferromagnetic exchange field-controlled band dispersions of non-Dirac electrons

Abstract

Using model analysis and first-principles calculations, we demonstrate that intrinsic ferromagnetic field of materials can effectively modulate the non-Dirac band dispersions. The four-bands k·p model illustrates that rotating magnetization from in-plane to out-of-plane lifts the degeneracy of band dispersions at Γ point, and spin components of lower or upper two bands tend to become identical as the enhancement of exchange field, which results in non-trivial topology. Moreover, we exemplify these phenomena in stanene-based systems, namely stanene/hematene heterostructure and half-hydrogen-passivated stanene, respectively. Some interesting spin-dependent transport behavior, such as large magnetoresistance and quantum anomalous hall effect, are achieved. These findings enrich the physics of non-Dirac electrons and provide promising routes for realizing effective manipulation of band dispersions via spin freedom.