A. Volker et P. Kopietz, SCREENING OF PERSISTENT CURRENTS IN MESOSCOPIC METAL RINGS, Zeitschrift fur Physik. B, Condensed matter, 102(4), 1997, pp. 545-551
The effect of the Coulomb-interaction on persistent currents in disord
ered mesoscopic metal rings threaded by a magnetic flux phi is studied
numerically. We use the simplest form of self-consistent Hartree theo
ry, where the spatial variations of the self-consistent Hartree potent
ial are ignored. In this approximation the self-consistent Hartree ene
rgies are simply obtained by diagonalizing the non-interacting system
via the Lanczos method and then calculating the (disorder-dependent) p
article number on the ring self-consistently. In the diffusive regime
we find that the variance of the total particle number is strongly red
uced, in agreement with the prediction of the random-phase approximati
on. On the other hand, the variance of the number of energy levels in
a small interval below the Fermi energy is not affected by the Coulomb
interaction. We argue that this implies that the experimentally obser
ved enhancement of the persistent current is due to long-range Coulomb
interactions.