Random magnetic field and weak localization effects in a dimpled 2D electron gas

We have studied negative magnetoresistance due to the weak localization effects in a 2D electron gas (2DEG) grown on dimpled substrates. Since the 2DEG is sensitive only to the normal component of B, depending on the orientation of the external magnetic field, electrons will move in a spatially inhomogeneous (B perpendicular to the substrate-B-perpendicular to) or sign alternating, random magnetic field (B parallel to the substrate B-parallel to). A difference in the magnetoresistance at B-parallel to and B-perpendicular to is seen for the sample with a coherence length larger than the spatial periodicity of magnetic field. We believe that the difference in the magnetic flux through the closed electron trajectories at B-parallel to and B-perpendicular to, taken into account random character of B-parallel to, is responsible for this behaviour. Features connected with Aharonov Bohm flux through the different areas on the dimpled surface were observed. (C) 1995 Academic Press Limited