Magnetotransport in a parabolic channel exposed to a periodically modulated magnetic held

We have studied the energy spectrum and magnetotransport of a parabolic one -dimensional channel in the presence of periodic modulations in both magnet ic field and the electrostatic potential. The periodic modulations change t he sub-band energy-wave-vector relation and produce mini-gaps at specific w ave-vectors. The gaps exist even if there is only modulation in the magneti c field. For the cases where the two kinds of modulation are in phase or ou t of phase, we give the explicit expressions for the values of the gaps. In the ballistic transport regime, the conductance-is expected to remain quan tized and to evolve in a simple manner as a function of the Fermi energy. S tarting from linear response theory, the transport properties are studied n umerically, taking into account the impurity scattering. Calculations relat ed to magnetic field modulation show that a series of cusps in the conducta nce are produced, whose magnitude depends strongly on the degree of impurit y scattering. The structure of these cusps can be explained in terms of the energy band structure.