arXiv: Superconductivity | 2019
Evidence of energy-level quantization in YBa2Cu3O7-x phase-slip nanowires
Abstract
Superconducting nanowires are considered to be promising for the development of novel devices operating on quantum principles. We fabricated ultra-thin YBa2Cu3O7-x nanowires with phase-slip dynamics and studied the switching-current statistics at temperatures below 20 K. We analyze our experimental data using theoretical models developed for the underdamped Josephson junction and find that they provide strong evidence of the energy-level quantization in these nanowires. The estimated crossover temperature between the thermal activation and the macroscopic quantum tunneling regimes is 12-13 K and the lifetime in the excited state exceeds 20 msec at T = 5.4 K, which is at least one order of magnitude superior to those parameters for the conventional tunnel Josephson junctions from low-temperature superconductors. Additionally, we demonstrate phase-slip and quantum mechanisms for single-photon detection by the phase-slip nanowire. Our findings pave the way for a new class of superconducting nanowire devices that can be used for quantum sensing and computing.