Resonance Energy and Charge Pumping through Quantum SINIS Contacts

We propose a mechanism of quantum pumping mediated by the spectral flow in a voltage-biased superconductor/insulator/normal-metal/insulator/superconductor quantum junction and realized via the sequential closing of the minigaps in the energy spectrum in resonance with the Josephson frequency. We show that the pumped dc current exhibits giant peaks at rational voltages.

Figure 1

Charge pump through a quantum channel with a variable chemical potential. The bias voltage is $V=V_L-V_R$.

Figure 2

Energy spectra Eq. (5) for a SINIS contact with $Z=0.5$ and $\Delta d/\hslash v_x=10$. (a) Dark lines: in the resonance $\sin {\alpha }^{\prime }=0$; light (red online) lines: in the antiresonance $|\sin {\alpha }^{\prime }|=1$. (b) Paths connecting states below $-|\Delta |$ to those above $+|\Delta |$ for trajectories $m=n=0$ of Fig. 3.

Figure 3

Linear resonance trajectories.