Spin-flip effects on the Andreev bound states and supercurrents in a superconductor/quantum-dot/superconductor system

TL;DR

This paper explores how spin-flip scattering in a superconductor/quantum-dot/superconductor system affects Andreev bound states and supercurrents, revealing controllable 0-$ ext{π}$ junction transitions.

Contribution

It provides a theoretical analysis of spin-flip effects on supercurrent reversal and $ ext{π}$-junction transitions via quantum dot energy level control.

Findings

Spin-flip scattering can reverse supercurrent and induce $ ext{π}$-junction transition.

Adjusting quantum dot energy level can reverse supercurrent back and cause another $ ext{π}$-transition.

Different effects of spin-flip scattering and energy level on supercurrent are explained through Andreev bound states.

Abstract

We investigate the spin-flip effects on the Andreev bound states and the supercurrent in a superconductor/quantum-dot/superconductor system theoretically. The spin-flip scattering in the quantum dot can reverse the supercurrent flowing through the system, and one $\pi$-junction transition occurs. By controlling the energy level of quantum dot, the supercurrent is reversed back and another $\pi$-junction transition appears. The different influences of the spin-flip scattering and the intradot energy level on the supercurrent are interpreted in the picture of Andreev bound states.