Mayumi Kato, Akira Endo, Shingo Katsumoto, and Yasuhiro Iye Institute for Solid State Physics, University of Tokyo, Roppongi, Minato-ku, Tokyo 106, Japan
(submitted to Phys.Rev.Lett.)
Abstract: We have studied transport in two-dimensional electron gas at a GaAs/AlGaAs heterointerface placed in a spatially alternating magnetic field. The effect of the periodic magnetic field is twofold. One is the effective mass renormalization which manifests itself as resistivity enhancement in the $T \rightarrow 0$ limit. The other is a $T^2$-dependent relaxation rate which is attributed to the electron-electron umklapp scattering. A similar phenomenon observed at higher values of bias current provides an additional support to this interpretation and forms a basis for a new method of hot electron thermometry.