Theory of Quenching of the Hall Resistance in Ballistic Microstructures.

We present both calculations and a physical interpretation of the observed suppression ("quenching") of the low-field Hall resistance in quasi-one-dimensional ballistic microstructures. We find that quenching is not intrinsic to this limit and does not occur generically in strongly coupled wires of constant width. Generic quenching is found only when the width of the wires is gradually increased near the junction to the Hall probes as in the experimental systems studied. This results in a collimation of the electrons in the forward direction which reduces the sensitivity to a weak magnetic field.