Magnetoconductance oscillations in semiconductor-superconductor junctions with a laterally isolating barrier layer inside semiconductor region

Abstract

The oscillatory characteristics of magnetoconductance for a junction composed of a superconductor and a semiconductor, in which two parallel quantum wave guides are coupled with each other through a potential barrier layer, are studied systematically. To model the imperfectness of the interface, we introduce a delta-function scattering potential barrier lying close to the interface of the junction. The magnetoconductance oscillations (MCO) in this system stem from two sources: one is the interference of wave functions of quasi-particles due to multiple Andreev reflections at the interface; the other is attributed to the variation of the number of the propagation modes when introducing the isolating barrier layer. The introduction of the isolating layer in the quantum wave-guides strongly modifies MCO. We also present a physical picture for the MCO based on a phenomenological argument. The theoretically fitted results are in good agreement with numerical ones.