OBSERVATION OF SCREENING IN THE MAGNETO-COULOMB DRAG BETWEEN COUPLED 2-DIMENSIONAL ELECTRON-SYSTEMS

The coupling between two spatially separated two-dimensional electron gases is studied as a function of magnetic field B. We find oscillatio ns in the transresistivity R(T), which are up to 2 orders of magnitude enhanced compared to the B = 0 case. R(T) vanishes in the regime of a quantum Hall plateau and shows a twin-peaked structure in the inter-p lateau regions. This observation is in good agreement with a recent th eory by M. C. Bonsager Et al. [Phys. Rev. Lett. 77, 1366 (1996)] who p redicted a similar behavior caused by the interplay of screening and L andau quantization.