Quantum Interference Effects in InAs Semiconductor Nanowires

TL;DR

This paper investigates quantum interference effects in InAs nanowires with superconducting contacts, revealing conductance fluctuations, enhancement due to Andreev reflection, and anomalous quantization at higher temperatures.

Contribution

It provides experimental evidence of quantum interference phenomena in InAs nanowires, including conductance fluctuation behavior and charge doubling effects in the superconducting state.

Findings

Universal conductance fluctuations match theoretical predictions.

Superconducting state shows enhanced fluctuations due to Andreev reflection.

Conductance quantization in steps of e^{2}/h observed above 4.2 K.

Abstract

We report quantum interference effects in InAs semiconductor nanowires strongly coupled to superconducting electrodes. In the normal state, universal conductance fluctuations are investigated as a function of magnetic field, temperature, bias and gate voltage. The results are found to be in good agreement with theoretical predictions for weakly disordered one-dimensional conductors. In the superconducting state, the fluctuation amplitude is enhanced by a factor up to ~ 1.6, which is attributed to a doubling of charge transport via Andreev reflection. At a temperature of 4.2 K, well above the Thouless temperature, conductance fluctuations are almost entirely suppressed, and the nanowire conductance exhibits anomalous quantization in steps of e^{2}/h.