Carrier flow and nonequilibrium superconductivity in superconductor-based light-emitting diode

TL;DR

This paper investigates the transport properties and nonequilibrium superconductivity in superconductor-based LEDs, demonstrating gate-controlled Josephson effects and modulation of critical current by ultralow currents, revealing insights into carrier flow and quasiparticle dynamics.

Contribution

It introduces a novel superconductor-based LED device exhibiting gate-controlled Josephson effects and analyzes nonequilibrium superconductivity and carrier flow mechanisms.

Findings

Realization of a new-type Josephson field effect transistor (JoFET) performance.

Modulation of superconducting critical current by pA-order steady current injection.

High sensitivity of radiative recombination process explained by quasiparticle conversion.

Abstract

Superconductor-based light-emitting diode (superconductor-based LED) in strong light-confinement regime are characterized as a superconductor-based three-terminal device, and its transport properties are quantitatively investigated. In the gate-controlled region, we confirm the realization of new-type Josephson field effect transistor (JoFET) performance, where the channel cross-sectional area of the junction is directly modulated by the gate voltage. In the current-injected region, the superconducting critical current of $\mu$A order in the Josephson junction is found to be modulated by the steady current injection of pA order. This ultrahigh monitoring sensitivity of the radiative recombination process can be explained by taking into account the fact that the energy relaxation of the absorbed photons causes the conversion of superconducting pairs to quasiparticles in the active layer. Using quasiparticle density and superconducting pair density, we discuss the carrier flows together with the non-equilibrium superconductovity in the active layer and the superconducting electrodes, which take place for compensating the conversion.