Universal Conductance Fluctuations in InAs/Al Hybrid Nanowires

The universal conductance fluctuations (UCF) observed in phase coherent, diffusive systems exhibit an amplitude quantized according to whether basic symmetries – e.g., time reversal symmetry – are preserved or broken [1]. While UCF has been extensively used to study symmetries in normal metal wires, systems with superconducting correlations, particularly normal-superconductor (NS) hybrid structures, have received less attention despite predictions that such systems possess unique symmetries. Here, we study symmetries in high-mobility selective area-grown nanowires [2] featuring an epitaxial InAs/Al interface [3] via UCF amplitude. In addition to time-reversal and spin-orbit symmetries, Andreev reflection also contributes to the UCF amplitude, and the related symmetry is broken by temperature, magnetic field, and voltage bias. The quantized amplitudes are consistent with predictions for a clean NS interface NW, where Andreev interference-driven enhanced weak localization is significant.