Resonant tunneling through Andreev levels

TL;DR

This paper investigates how resonant tunneling through Andreev levels in a normal-superconductor contact leads to oscillating excess conductance, revealing phase-dependent quantum transport phenomena at low temperatures.

Contribution

It introduces a semiclassical method to analyze resonant tunneling via Andreev levels, highlighting phase-dependent conductance oscillations at low temperatures.

Findings

Resonant transmission through Andreev levels enhances conductance.

Excess conductance oscillates with the phase difference between superconductors.

Maxima occur at odd multiples of π at low temperatures.

Abstract

We use a semiclassical approach for analysing the tunneling transport through a normal conductor in contact with superconducting mirrors. Our analysis of the electron-hole propagation along semiclassical trajectories shows that resonant transmission through Andreev levels is possible resulting in an excess, low-energy quasiparticle contribution to the conductance. The excess conductance oscillates with the phase difference between the superconductors having maxima at odd multiples of $\pi$ for temperatures much below the Thouless temperature