Andreev reflection adjusting in the multi-terminal device with the kink states

TL;DR

This paper investigates how kink states at domain walls in topological materials influence Andreev reflections in a multi-terminal device, revealing controllable reflection coefficients for potential quantum device applications.

Contribution

It introduces a multi-terminal device design utilizing kink states to control local and crossed Andreev reflections through phase and energy adjustments.

Findings

Crossed Andreev reflection coefficient can reach 1.

Reflection processes are tunable via phase, on-site energy, and stagger energy.

Kink states provide robustness for quantum device design.

Abstract

At the domain wall between two regions with the opposite Chern number, there should be the one-dimensional chiral states, which are called as the kink states. The kink states are robust for the lattice deformations. We design a multi-terminal device with the kink states to study the local Andreev reflection and the crossed Andreev reflection. The coefficient of the crossed Andreev reflection can reach 1 in the four-terminal device. Besides adjusting the phase difference between superconductors, the local Andreev reflection and the crossed Andreev reflection can be controlled by changing the on-site energy and the stagger energy in the four-terminal device. Our results give some new ideas to design the quantum device in the future.