Proposal for Superconducting Photodiode

TL;DR

This paper introduces a superconducting photodiode concept that converts electromagnetic energy and spin into a steady supercurrent, supported by a microscopic theory for thin films under specific conditions.

Contribution

It proposes a novel superconducting photodiode design and develops a microscopic theory describing its properties and the conditions for supercurrent generation.

Findings

Prediction of photoexcited quasiparticle current.

Emergence of stationary supercurrent flow.

Dependence of supercurrent on material and electromagnetic properties.

Abstract

We propose a concept of a superconducting photodiode - a device that transforms the energy and `spin' of an external electromagnetic field into the rectified steady-state supercurrent and develop a microscopic theory describing its properties. For this, we consider a two-dimensional thin film cooled down below the temperature of superconducting transition with the injected dc supercurrent and exposed to an external electromagnetic field with a frequency smaller than the superconducting gap. As a result, we predict the emergence of a photoexcited quasiparticle current, and, as a consequence, oppositely oriented stationary flow of Cooper pairs. The strength and direction of this photoinduced supercurrent depend on (i) such material properties as the effective impurity scattering time and the nonequilibrium quasiparticles' energy relaxation time and (ii) such electromagnetic field properties as its frequency and polarization.