Cooper pair tunnelling into a Quantum Hall fluid

TL;DR

This paper theoretically investigates Cooper pair tunnelling into a quantum Hall fluid, revealing a temperature-dependent conductance that vanishes at low temperatures except at certain integer fillings where conductance persists.

Contribution

It introduces a model for Cooper pair tunnelling into quantum Hall edge states, highlighting the effects of Coulomb and Pauli exclusion, and predicts conductance behavior at various filling factors.

Findings

Conductance vanishes as T^{4/ν - 2} for certain fillings

At integer fillings greater than 1, conductance remains non-zero

Tunnelling is suppressed at low energies due to Coulomb and Pauli effects

Abstract

Transport through a tunnel junction connecting a superconductor to a spin-aligned quantum Hall fluid at filling $\nu$ is studied theoretically. The dominant transport channel at low temperatures is the tunnelling of Cooper pairs into edge states of the quantum Hall fluid. This process, which is greatly suppressed at low energies due to both Coulomb and Pauli exclusion effects, leads to a tunnelling conductance which vanishes with temperature as $T^{4/\nu -2}$, for $\nu^{-1}$ an odd integer. For integer fillings with $\nu >1$ the "Pauli blockade" is circumvented and a non-vanishing conductance is predicted.