Magnetotransport in corrugated quantum wires

The magnetoresistance of ballistic quantum wires with periodically modulated width has been calculated. We find that the negative magnetoresistance peak persists approximately up to 0.1 T, which is two orders of magnitude larger than in single quantum dots. Our results are in good agreement with recent experiments. We believe that the wide peak is a manifestation of a weak localization effect, arising from multiple backscattering and resonances among the segments of the corrugated wire. The weak localization effect is not sensitive to the period of corrugation, nor to the wire width, as long as the number of propagating modes is large. As random disorder is introduced, and the system approaches the diffusive transport regime, the wide negative magnetoresistance peak disappears.