Coherent photocurrent control in a magnetic field through quantum interference

We treat theoretically the coherent optical control of carrier and current densities in a semiconductor quantum well in the presence of a magnetic field perpendicular to the plane of the well by means of time-dependent perturbation theory. Photocurrents of electrons and holes are shown to be generated through quantum interference of one-and two-photon excitation pathways when the sample is exposed to two-color pulses, and we find that these currents rotate in time in opposite directions as a result of excitation by these pathways to or from different but adjacent Landau levels. The initial directions of the currents can be controlled by adjusting a relative phase parameter of the optical pulses. The magnitudes of the generated photocurrents are comparable to those predicted and detected in the absence of a magnetic field, and so the effects considered here should be observable.