Spin polarization and heat generation matching in a quantum dot with magnetic background

Abstract

Motivated by the increasing demand for designing spin-polarized quantum devices via electric manipulation, we theoretically studied the spin polarization induced by Rashba spin-orbit interaction (RSOI) and the heat generated by thermal bias in the normal metal(N)-(insulator(I), Quantum Dot(QD))-Superconductor(S) ring threaded by a magnetic flux. We observed that the effective dot level, ε¯d=0 or ε¯d=±ω02 (ω0: characteristic phonon frequency), is responsible for the outstanding spin polarization in different BCS gaps and that non-dissipative spin-polarized current is produced effectively by adjusting the RSOI strength and thermal bias. Furthermore, we concluded that the thermal bias accounts for the spin-polarized Andreev current through the s-wave superconducting electrode, rather than the electric bias. Overall, our work provides a novel method for producing non-dissipative pure spin current.