Quenching of the Hall resistance in a novel geometry

We have observed quenching of the Hall resistance in a GaAs-${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As heterostructure Hall junction containing four narrow constrictions leading into a quantum dot. Backgated junctions show quenching within a broad but finite electron density range. In contrast, junctions containing fewer constrictions show little or no quenching behavior. These results show conclusively that the nature of the junction region is crucial in producing quenching and can be explained in terms of junction scattering using Buttiker-Landauer formulas.