Charge Induction and Polarization on the Surface of a Topological Insulator Due to an Emergent Gauge Field

Abstract

Exchange interaction with surface magnetization exerts a local U(1) gauge field on Dirac fermions that exist on the surface of a topological insulator (TI). We show that the emergent gauge field gives rise to charge induction and polarization on the TI surface via the quantum anomalous Hall (QAH) effect. These phenomena correspond to an implementation of the Laughlin’s thought experiment [R. B. Laughlin, Phys. Rev. B 23, 5632 (1981)] without inserting a magnetic flux, and enable a local evaluation of the QAH transport on a specific TI surface.