MAGNETORESISTANCE CALCULATIONS FOR A QUANTUM-WIRE WITH PERIODICALLY MODULATED WIDTH

We present numerical calculations of the magnetoresistance in a ballis tic quantum wire with periodically modulated width. Surprisingly, the negative magnetoresistance peak is found to persist to a field strengt h which is two orders of magnitude larger than in single quantum dots. In the weak B-field regime, our results are in, good agreement with r ecent experiments. We argue that the wide peak is due to multiple back scattering among the segments of the wire, leading to a novel weak loc alization effect. (C) 1996 Academic Press Limited