title: Scale-dependent competing interactions: sign reversal of the average persistent current.
abstract: The interaction-induced orbital magnetic response of a nanoscale system, modeled by the persistent current in a ring geometry, is evaluated for a system which is a superconductor in the bulk. The interplay of the renormalized Coulomb and Fröhlich interactions is crucial. The diamagnetic response of the large superconductor may become paramagnetic when the finite-size-determined Thouless energy is larger than or on the order of the Debye energy.
authors: Physics Department, Ben Gurion University, Beer Sheva 84105, Israel.
authors: H
authors: H
authors: Bary-Soroker
authors: O
authors: O
authors: Entin-Wohlman
authors: Y
authors: Y
authors: Imry
authors: A
authors: A
authors: Aharony