Spin pump in the presence of a superconducting lead

Yanxia Xing; Bin Wang; Yadong Wei; Baigeng Wang; Jian Wang

doi:10.1103/PhysRevB.70.245324

← Back to search

Spin pump in the presence of a superconducting lead

Yanxia Xing, Bin Wang, Yadong Wei, Baigeng Wang, Jian Wang

DOI 10.1103/PhysRevB.70.245324 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We present a theoretical analysis of a spin pump in the presence of a superconducting lead. The spin pump is facilitated by a rotating magnetic field which provides a spin flip mechanism and hence can generate a spin current without an accompanying charge current. Using a nonequilibrium Green’s function method, we obtain a general solution of the pumped charge current and spin current in both the adiabatic and non-adiabatic regimes. The numerical results for the charge current and spin current are presented as we vary different system parameters such as the gate voltage, the external magnetic field, and the pumping frequency. We find that for a quantum dot with a single resonant level in line with the Fermi energy of the left normal lead, a pure spin current is generated by a rotating magnetic field at any frequency. We have identified two kinds of photon-assisted processes which dominate at low pumping frequencies and high pumping frequencies, respectively.