Magnetotransport in a spatially modulated magnetic field

We have measured the Shubnikov de Haas (SdH) oscillations of a nonplanar tw o-dimensional electron gas (2DEG) fabricated by overgrowth of a GaAs/AlGaAs heterojunction on a pre-patterned substrate. When placed in a uniform exte rnal magnetic field B, the field normal to the nonplanar 2DEG is spatially modulated, and electrons experience a nonuniform magnetic field. In a tilte d magnetic field, the SdH oscillations are much more strongly damped than i n a field perpendicular to the substrate. We consider several mechanisms an d conclude that the electron scattering by the magnetic field spatial fluct uations plays a main role in the transport properties of a nonplanar 2DEG a t low magnetic field.