In-plane FFLO instability in superconductor-normal metal bilayer system under non-equilibrium quasiparticle distribution

TL;DR

This paper predicts a new in-plane FFLO instability in superconductor-normal metal bilayers under non-equilibrium conditions, controllable by voltage, without requiring Zeeman interaction, and detectable via magnetic flux and temperature response.

Contribution

It introduces the possibility of observing in-plane FFLO states in S/N heterostructures under non-equilibrium conditions without Zeeman interaction, expanding the understanding of FFLO phenomena.

Findings

FFLO states can be induced in S/N bilayers near T_c under non-equilibrium conditions.

Different FFLO configurations, including 2D structures, are theoretically possible.

Some FFLO states generate magnetic flux observable experimentally.

Abstract

It is predicted that a new class of systems - superconductor/normal metal (S/N) heterostructures can reveal the in-plane Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) instability under nonequilibrium conditions at temperatures close to the critical temperature. It does not require any Zeeman interaction in the system. For S/N heterostructures under non-equilibrium distribution there is a natural easily adjustable parameter - voltage, which can control the FFLO-state. This FFLO-state can be of different types: plane wave, stationary wave and, even, 2D-structures are possible. Some types of the FFLO-state are accompanied by the magnetic flux, which can be observed experimentally. All the types of the FFLO-state can reveal through the temperature dependence of the linear response of the system on the applied magnetic field near $T_c$, which strongly differs from that one for the homogeneous state.