Tunable magnetic-field asymmetry of nonlinear mesoscopic transport: Field-effect controlled backscattering in a quantum wire

The nonlinear conductance of quantum wires has been studied in magnetic fields by applying an in-plane electric field via side gates. It has been found that magnetic-field asymmetries, defined as the change in the conductance induced by a change in the magnetic-field sign, become more pronounced the larger the gate voltage is and increase linearly with the bias voltage up to several millivolts. With an in-plane electric field the asymmetry can be tuned, the symmetry recovered, and also the asymmetry reversed, which is associated with a field-effect controlled backscattering of electrons.