Role of edge and bulk currents through a gate barrier in nonlocal resistance of GaAs/AlxGa1-xAs

Nonlocal Shubnikov-Haas (SdH) oscillations have been measured in multiterminal GaAs/AsxGa1-xAs wires, where the Schottky gate lies across the nonlocal path between the nominal current and voltage paths. The influence of the bulk and edge states on the nonlocal resistance has been investigated by cutting the bulk and edge current at the gate. With decreasing gate voltage and carrier concentration underneath the gate, the SdH oscillation peaks of the down-spin Landau levels diminish at lower gate voltage than those of the up-spin levels. This could be explained by the fact that ''the bulk current'' corresponding to the down-spin Landau-level peak of the SdH oscillation comes from the overlapping down-spin and up-spin states, while the up-spin Landau-level peak comes from mostly the up-spin state.