Superconducting Proximity Effect in Silicene: Spin-Valley Polarized Andreev Reflection, Non-Local Transport, and Supercurrent

TL;DR

This paper theoretically investigates the superconducting proximity effect in silicene, demonstrating controllable spin-valley polarized Andreev reflection, non-local conductance, and supercurrent via external electric fields due to silicene's unique buckled structure.

Contribution

It introduces a method to control spin-valley polarized transport phenomena in silicene using external electric fields, highlighting novel fully spin-valley polarized Andreev processes.

Findings

Spin-valley polarized crossed Andreev reflection without contamination.

Controllable supercurrent that is fully spin-valley polarized.

External electric field enables efficient control of transport processes.

Abstract

We theoretically study the superconducting proximity effect in silicene, which features massive Dirac fermions with a tunable mass (band gap), and compute the conductance across a normal/superconductor (N/S) silicene junction, the non-local conductance of an N/S/N junction, and the supercurrent flowing in an S/N/S junction. It is demonstrated that the transport processes consisting of local and non-local Andreev reflection may be efficiently controlled via an external electric field owing to the buckled structure of silicene. In particular, we demonstrate that it is possible to obtain a fully spin-valley polarized crossed Andreev reflection process without any contamination of elastic cotunneling or local Andreev reflection, in stark contrast to ordinary metals. It is also shown that the supercurrent flowing in the S/N/S junction can be fully spin-valley polarized and that it is controllable by an external electric field.