Selective equal spin Andreev reflection at vortex core center in magnetic semiconductor-superconductor heterostructure

TL;DR

This paper investigates spin-polarized Andreev reflection at vortex cores in a magnetic semiconductor-superconductor heterostructure, revealing quantized conductance in the topological phase and spin selectivity influenced by spin-orbit coupling.

Contribution

It demonstrates spin-selective Andreev reflection and quantized conductance at vortex cores, distinguishing topological from trivial phases in the heterostructure.

Findings

Quantized differential conductance (2e^2/h) at vortex core in topological phase.

Spin selectivity of Andreev reflection influenced by spin-orbit coupling.

Suppression of Andreev reflection at zero bias in trivial phase due to quantum interference.

Abstract

Sau, Lutchyn, Tewari and Das Sarma (SLTD) proposed a heterostructure consisting of a semiconducting thin film sandwiched between an s-wave superconductor and a magnetic insulator and showed possible Majorana zero mode. Here we study spin polarization of the vortex core states and spin selective Andreev reflection at the vortex center of the SLTD model. In the topological phase, the differential conductance at the vortex center contributed from the Andreev reflection, is spin selective and has a quantized value $(dI/dV)^{topo}_A =2e^2/h$ at zero bias. In the topological trivial phase, $(dI/dV)^{trivial}_A$ at the lowest quasiparticle energy of the vortex core is spin selective due to the spin-orbit coupling (SOC). Unlike in the topological phase, $(dI/dV)^{trivial}_A$ is suppressed in the Giaever limit and vanishes exactly at zero bias due to the quantum destruction interference.