Suppression of non-equilibrium quasiparticle transport in flat band superconductors

TL;DR

This paper investigates non-equilibrium transport in flat band superconductors, revealing suppression of quasiparticle transport and dominance of coherent pair transport, with implications for high-temperature superconductivity and quasiparticle management.

Contribution

It demonstrates that flat band superconductors suppress quasiparticle transport and favor coherent pair transport, highlighting their potential for high-temperature applications and quasiparticle control.

Findings

Quasiparticle transport is suppressed in flat band superconductors.

Coherent pair transport dominates over quasiparticle transport.

AC supercurrent can overcome DC current in superconducting leads.

Abstract

We study non-equilibrium transport through a superconducting flat-band lattice in a two-terminal setup with the Schwinger-Keldysh method. We find that quasiparticle transport is suppressed and coherent pair transport dominates. For superconducting leads, the AC supercurrent overcomes the DC current which relies on multiple Andreev reflections. With normal-normal and normal-superconducting leads, the Andreev reflection and normal currents vanish. Flat band superconductivity is thus promising not only for high critical temperatures but also for suppressing unwanted quasiparticle processes.