Resistance jumps and the nature of the finite-flux normal phase in ultra-thin superconducting cylinders

Abstract

Recent observations have revealed the emergence of an unusual normal phase when a magnetic flux threads an ultra-thin superconducting cylinder. Moreover, with increasing temperature, the resistance rises in a series of abrupt jumps. These phenomena are explained using a novel approach, which allows calculation of the resistance in the presence of amplitude and phase fluctuations of the superconducting order parameter, and at the same time introduces a local probe of the current and chemical potential. It is demonstrated that phase fluctuations lead to the sequential breakdown of local superconducting phase correlations, resulting in the formation of normal weak links, which give rise to the emergence of the normal phase is a stepwise manner. Finally, specific predictions are made on how the experimental observations change with the cylinder geometry.