Newly Observed Phase Coherent Electron Transport Properties in the Mesoscopic Loop Structure of Aluminum Wire

Abstract

We have identified two new features related to the coherent transport in the mesoscopic loop structure of aluminum wire, including the autocorrelation of the conductance fluctuations beyond Bc and fine structure in the low-field magnetoresistance curve in the superconducting transition regime, which, to the best of our knowledge, have not been reported in the literature. Since the electrons in Al have a phase coherence length larger than 1 μm at or below T = 3 K, which is comparable to the dimensions of the structure, the wave nature of the electronic transport has been clearly observed: the universal conductance fluctuations, the Aharonov-Bohm oscillations, and the Altshuler-Aronov-Spivak oscillations. Due to the transition of Al to a superconducting state at T = 1.3 K, the coherent phenomena of Cooper pairs, i.e., the Little-Parks oscillations, have also been observed.