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 calcu lations for two-dimensional electron systems in the presence of periodic el ectric and magnetic modulation fields, both in the regime of the low-field positive magnetoresistance and of the Weiss oscillations at intermediate Va lues of the applied magnetic field. We solve Boltzmann's equation by the me thod of characteristics, which allows to exploit explicitly information abo ut the structure of the phase space. This structure becomes very complicate d if the amplitudes of the modulation fields become so large and the averag e magnetic field becomes so small that, in addition to the drifting cyclotr on orbits, channeled orbits exist and drifting cyclotron orbits extend over many periods of the modulation. (C) 1998 Elsevier Science B.V. All rights reserved.