Intralayer backscattering in narrow GaAs/Al_xGa_1-xAs/GaAs bilayer channels

We study the magnetoresistance R_xx, and the Hall resistance Rxy in GaAs/Al_xGa_1-xAs/GaAs bilayer systems, in which the electron channel of each layer is latterally confined in a narrow Hall bar of width W=0.3–5μm. We observe that intralayer backscattering destroy some states peculiar to the bilayer system. Rxy plateaus at odd filling factors largely deviate from their integer values in monolayer quantum Hall (QH) states due to backscattering, while the normal R_xy plateau is observed from coupled QH states. Examining the backscattering both in the Hall bars and in their voltage probes, we discuss the suppression of the intralayer backscattering between edge channels strongly modified by the interlayer charge transfer between the front and the back channels.