Control of magnetic field modulation on two-dimensional electron gas at the GaAs/AlGaAs heterointerface by parallel magnetic field

We have studied the magnetoresistance oscillation (Weiss oscillation) in a two-dimensional electron gas (2DEG) subjected to a one-dimensional periodic modulation of magnetic field. Magnetic field modulation was produced by placing nickel grating on the surface of 2DEG wafer and applying a magnetic field B-parallel to parallel to the 2DEG plane. We show that tie amplitude of the magnetic modulation can be varied by rotating B-parallel to with respect to the grating. independent of the perpendicular field B-perpendicular to used for the measurement of magnetoresistance. With decreasing magnetic modulation amplitude, the magnetoresistance oscillation loses its amplitude without shifting the phase, until peak-to-valley inversion takes place. This demonstrates that the magnetic modulation thus produced is spatially out-of-phase with the small residual electrostatic potential modulation inevitably brought about by the grating. (C) 1998 Elsevier Science Ltd. All rights reserved.