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

TL;DR

This paper demonstrates that spin-sensitive scattering at interfaces in superconducting hybrids can create electron-hole imbalance, leading to a significant thermoelectric effect comparable to the superconductor's critical current.

Contribution

It reveals a physical mechanism where spin-active interfaces induce electron-hole imbalance, resulting in large thermoelectric effects in superconducting hybrids.

Findings

Electron-hole imbalance can be generated by spin-sensitive scattering.

Thermoelectric current can reach the magnitude of the superconductor's critical current.

Explicit expressions for thermoelectric current in superconducting-normal bilayers are derived.

Abstract

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 electron-like and hole-like 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.