Magnetoresistance of a two-dimensional electron gas in a one-dimensional superlattice defined by strong modulation fields

Boltzmann's equation provides an adequate starting point of transport calculations for two-dimensional electron systems in the presence of periodic electric and magnetic modulation fields, both in the regime of the low-field positive magnetoresistance and of the Weiss oscillations at intermediate Values of the applied magnetic field. We solve Boltzmann's equation by the method of characteristics, which allows to exploit explicitly information about the structure of the phase space. This structure becomes very complicated if the amplitudes of the modulation fields become so large and the average magnetic field becomes so small that, in addition to the drifting cyclotron orbits, channeled orbits exist and drifting cyclotron orbits extend over many periods of the modulation. (C) 1998 Elsevier Science B.V. All rights reserved.