Effect Of Berry Phase On Nonlinear Response Of Two-Dimensional Fermions

We develop a theory of nonlinear response to an electric field of two-dimensional (2D) fermions with topologically nontrivial wave functions characterized by the Berry phase Phi(n) = n pi, n = 1, 2, . . .. In particular, we find that owing to the suppression of backscattering at odd n, Hall field-induced resistance oscillations, which stem from elastic electron transitions between Hall field-tilted Landau levels, are qualitatively distinct from those at even n: Their amplitude decays with the electric field and their extrema are phase shifted by a quarter cycle. The theory unifies the cases of graphene (n = 1) and graphite bilayer (n = 2) with the case of conventional 2D electron gas (n = 0) and suggests another method to probe backscattering in topological 2D systems.