Anomalous Hall effect and persistent valley currents in graphene p-n junctions/

Abstract

Dirac particles can exhibit Hall-like transport induced by Berry's gauge field in the absence of magnetic field. We develop a detailed picture of this unusual effect for charge carriers in graphene nanostructures. The Hall effect is nonzero in each valley but is of opposite signs in different valleys, giving rise to charge-neutral valley currents. Our analysis reveals that p-n junctions in graphene support persistent valley currents that remain nonzero in the system ground state (in thermodynamic equilibrium). The valley currents can be controlled via the bias and gate voltages, enabling a variety of potentially useful valley transport phenomena.