Spin-dependent Andreev reflection tunneling through a quantum dot with intradot spin-flip scattering

TL;DR

This paper investigates how intradot spin-flip interactions influence Andreev reflection tunneling through a quantum dot connected to ferromagnetic and superconducting leads, revealing resonance behaviors and spectral structures.

Contribution

It introduces a theoretical analysis of AR conductance considering intradot spin-flip scattering, highlighting the transition from single to double peak resonances with increasing spin-flip strength.

Findings

Weak spin-flip scattering causes a single resonance peak.

Strong spin-flip scattering results in a double peak resonance.

The study details effects of spin-dependent tunneling and ferromagnet polarization.

Abstract

We study Andreev reflection (AR) tunneling through a quantum dot (QD) connected to a ferromagnet and a superconductor, in which the intradot spin-flip interaction is included. By using the nonequibrium-Green-function method, the formula of the linear AR conductance is derived at zero temperature. It is found that competition between the intradot spin-flip scattering and the tunneling coupling to the leads dominantes resonant behaviours of the AR conductance versus the gate voltage.A weak spin-flip scattering leads to a single peak resonance.However, with the spin-flip scattering strength increasing, the AR conductance will develop into a double peak resonannce implying a novel structure in the tunneling spectrum of the AR conductance. Besides, the effect of the spin-dependent tunneling couplings, the matching of Fermi velocity, and the spin polarization of the ferromagnet on the AR conductance is eximined in detail.