Electron-hole imbalance and large thermoelectric effect in superconducting hybrids with spin-active interfaces

We argue that spin-sensitive quasiparticle scattering may generate electron-hole imbalance in superconducting structures, such as, e.g., superconducting-normal hybrids with spin-active interfaces. We elucidate a transparent physical mechanism for this effect demonstrating that scattering rates for electrons and holes at such interfaces differ from each other. Explicitly evaluating the wave functions of electronlike and holelike excitations in superconducting-normal bilayers we derive a general expression for the thermoelectric current and show that-in the presence of electron-hole imbalance-this current can reach maximum values as high as the critical current of a superconductor.