2012/03/29 by J. Feilhauer, Feilhauer, J., M. Mosko +1 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.1203.6512
arxiv created 2012/12/14 · arxiv updated 2012/12/17
Typical persistent current (Ityp) in a normal metal ring with disorder due to random grain boundaries and rough edges is calculated microscopically. If disorder is due to the rough edges, a ballistic current Ityp≃ e vF/L is found in spite of the diffusive resistance ( ∝ L/l), where vF is the Fermi velocity, l is the mean free path, and L ≫ l is the ring length. This ballistic current has a simple interpretation: It is due to a single coherent electron that moves in parallel with the edges and thus does not feel the roughness. Our calculations explain a puzzling experimental result Ityp≃ e vF/L, reported by Chandrasekhar et al. [Phys. Rev. Lett. 67, 3578 (1991)] for metal rings of length L ≃ 100 l. If disorder is due to the grain boundaries, our results agree with diffusive result Ityp≃ (e vF/L) (l/L), derived by Cheung et al. [Phys. Rev. Lett. 62, 587 (1989)] and observed by Bluhm et al. [Phys. Rev. Lett. 102, 136802 (2009)] and Bleszynsky-Jayich et al. [Science 326, 272 (2009)].