Electrical control of crossed Andreev reflection and spin-valley switch in antiferromagnet/superconductor junctions

We study the subgap transport through the antiferromagnet/superconductor (AF/S) and antiferromagnet/superconductor/antiferromagnet (AF/S/AF) junctions controlled by electric field in a generic buckled honeycomb system, such as silicene, germanene, and stanene. In the presence of electric field and antiferromagnetic exchange field, the spin-valley polarized half-metallic phase can be achieved in the honeycomb system due to the spin-orbit coupling, which affords an opportunity to generate the pure crossed Andreev reflection (CAR). It is found that the pure CAR can be generated without local Andreev reflection (AR) and elastic cotunneling (EC) over a wide range of electric field. A spin-valley switch effect can be realized between the pure CAR and the pure EC by adjusting the electric field. The properties of AR process and CAR process strongly depend on the spin-valley polarized states. Our results suggest that the device can implement an electrical measurement of the CAR process and spin-valley switch.

Automated summary

In this study, subgap transport through AF/S and AF/S/AF junctions controlled by electric field in a buckled honeycomb system was investigated. The spin-valley polarized half-metallic phase and pure crossed Andreev reflection were achieved due to spin-orbit coupling, with the possibility of generating the pure CAR without AR and EC. A spin-valley switch effect could be realized by adjusting the electric field, and the properties of AR and CAR processes strongly depended on the spin-valley polarized states. The device could potentially be used for electrical measurement of the CAR process and spin-valley switch.