Dephasing-enabled triplet Andreev conductance

TL;DR

This paper investigates how dephasing influences triplet Andreev conductance in chaotic quantum dots with strong spin-orbit coupling, revealing nonmonotonic fluctuation behavior as dephasing varies.

Contribution

It provides the first full distribution of conductance in such systems as a function of dephasing rate, highlighting nonmonotonic fluctuation dependence.

Findings

Dephasing enables nonzero conductance in the quantum limit.

Conductance fluctuations depend nonmonotonically on dephasing rate.

Zero-temperature, zero-bias conductance can be controlled via dephasing.

Abstract

We study the conductance of normal-superconducting quantum dots with strong spin-orbit scattering, coupled to a source reservoir using a single-mode spin-filtering quantum point contact. The choice of the system is guided by the aim to study triplet Andreev reflection without relying on half metallic materials with specific interface properties. Focusing on the zero temperature, zero-bias regime, we show how dephasing due to the presence of a voltage probe enables the conductance, which vanishes in the quantum limit, to take nonzero values. Concentrating on chaotic quantum dots, we obtain the full distribution of the conductance as a function of the dephasing rate. As dephasing gradually lifts the conductance from zero, the dependence of the conductance fluctuations on the dephasing rate is nonmonotonic. This is in contrast to chaotic quantum dots in usual transport situations, where dephasing monotonically suppresses the conductance fluctuations.