Quantum Interference Effects in InAs Semiconductor Nanowires

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 the magnetic field, the temperature, the bias and the 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 similar to 1.6, which is attributed to a doubling of the 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.