SELFCONSISTENT CURRENT-VOLTAGE CHARACTERISTICS OF NORMAL-SUPERCONDUCTOR INTERFACES

TL;DR

This paper investigates the nonlinear electrical behavior of normal-superconductor interfaces using a self-consistent microscopic approach, revealing how superfluid velocity and temperature influence quasiparticle transmission and superconductivity stability.

Contribution

It provides a detailed microscopic analysis of NS and NSN structures, highlighting the effects of superfluid velocity, quasiparticle scattering, and temperature on transport properties and superconductivity.

Findings

Superfluid velocity causes quasiparticle channels to open at different voltages.

Gap reduction is highly sensitive to quasiparticle scattering details.

Superconductivity can persist at voltages much higher than $k_B T_c/e$, especially at low temperatures.

Abstract

We study the nonlinear transport properties of NS (normal-superconductor) and NSN structures by means of a self-consistent microscopic description. A nonzero superfluid velocity causes the various quasiparticle channels within S to open at different voltages. The gap reduction is very sensitive to the details of quasiparticle scattering. At low temperatures, superconductivity, some times in a peculiar gapless form, may survive up to voltages much higher that $k_B T_c/e$. The minimum voltage for quasiparticle transmission is shown to decrease strongly with temperature and with the transmittivity of the barrier.