Reflectionless quantum transport and fundamental ballistic-resistance steps in microscopic constrictions
Glazman L. I. , Lesovik G. B., Khmel'nitskii D. E., Shekhter R. I.
A quantization of the resistance of microscopic constrictions in a two-dimensional electron gas [B. J. van Wees etal, Phys. Rev. Lett. 60,848 (1988); D. A. Wharam etal, J. Phys. 21, L209 (1988) ] arises if the constriction has a sufficiently smooth shape: τι2 yjlR /d > 1, where d and R are the diameter and radius of curvature of the constriction. The shape of the steps is shown to be related to the geometry of the constriction.