DISSIPATIVE DYNAMICS OF AN ELECTRONIC WAVEPACKET IN A SEMICONDUCTOR DOUBLE WELL POTENTIAL

We present a detailed study of coherent tunneling oscillations of an optically excited electronic wavepacket in a semiconductor double quantum-well structure. The oscillation of the wavepacket between the two wells is traced by time-resolved pump-probe spectroscopy as well as time-resolved degenerate four-wave mixing. The experimental observations are compared with a simple theoretical model. The motion of the wavepacket is studied as a function of both an external electric field and the lattice temperature. While the oscillation frequency shows the expected dependence on electric field, it increases with temperature at fixed electric field when perfectly delocalized electronic states exist at low temperature.