Parity effect in a mesoscopic superconducting ring

Department of Physics, Chonbuk National University - 664-14 1-ga Duckjin-Dong Duckjin-Gu Chonju, Chonbuk 561-756, South Korea

Corresponding author: kckang@phy0.chonbuk.ac.kr

Received: 24 November 1999
Accepted: 22 May 2000

Abstract

We study a mesoscopic superconducting ring threaded by a magnetic flux when the single-particle level spacing is not negligible. It is shown that, for a superconducting ring with even parity, the behavior of persistent current is equivalent to what is expected in a bulk superconducting ring. On the other hand, we find that a ring with odd parity shows anomalous behavior such as fluxoid quantization at half-integral multiples of the flux quantum and paramagnetic response at low temperature. We also discuss how the parity effect in the persistent current disappears as the temperature is raised or the size of the ring increases.