The persistent current in isolated mesoscopic rings is studied using the continuum and tight-binding models of independent electrons. The calculation is performed with disorder and also at finite temperature. In the absence of disorder and at zero temperature agreement is obtained with earlier results by Loss and Goldbart in that there is half-quantum flux periodicity for a large and odd number of electrons, but full-quantum periodicity for any even number of electrons in the ring. Strong disorder converts the period into full-quantum periodicity. Finite temperature reduces the magnitude of the current, but preserves the quantum flux periodicity at zero temperature. However, the sign of the current may change as disorder or temperature is increased. A generalization of the parity effect, previously discussed by Leggett, Loss, and Kusmartsev is described for the case where there are electrons with spin, influenced by finite temperature and disorder.
Physical Review B
- Pub Date:
- March 1994
- Galvanomagnetic and other magnetotransport effects;
- Electronic conduction in metals and alloys;
- Condensed Matter
- 17 pages(LaTeX), 4 figures by request, accepted by Phys. Rev. B and Technical Report of ISSP, Tokyo University