1203.6512 (J. Feilhauer et al.)

Ballistic-like persistent currents in disordered metallic rings: Origin
of large experimental values    [PDF]

J. Feilhauer, M. Mosko

Quantum physics predicts that a mesoscopic resistive metal ring will support a persistent current of size corresponding roughly to the current carried by a single electron diffusing around the ring at the Fermi energy. Recent experiments confirm this prediction, but a puzzle of mesoscopic physics is the milestone observation of currents resembling a single electron moving around the ring ballistically rather than diffusively. We explain this observation by calculating persistent currents in rings with realistic disorder. If disorder is due to polycrystalline grains, we find the diffusive current, like the recent experiments. However, if the grains are large and disorder is mainly due to the rough ring edges, we find the ballistic-like current even for the ring lengths hundred times larger than the electron mean free path, like in the milestone experiment. This current is due to a single coherent electron that moves (classically speaking) in parallel with the edges and thus does not feel the roughness.

View original: http://arxiv.org/abs/1203.6512