Coexistence of diffusive resistance and ballistic persistent current in disordered metallic rings with rough edges: Possible origin of puzzling experimental values

J. Feilhauer and M. Moško
Phys. Rev. B 88, 125424 – Published 19 September 2013

Abstract

Typical persistent current (Ityp) in a mesoscopic normal metal ring with disorder due to rough edges and random grain boundaries is calculated by use of a scattering matrix method. In addition, resistance of a corresponding metallic wire is obtained from the Landauer formula and the electron mean free path (l) is determined. If disorder is due to the rough edges, a ballistic persistent current ItypevF/L is found to coexist with the diffusive resistance (L/l), where vF is the Fermi velocity and Ll is the ring length. This ballistic current is due to a single electron that moves almost in parallel with the rough edges and thus hits them rarely (it is shown that this parallel motion exists in the ring geometry due to the Hartree-Fock interaction). Our finding agrees with a puzzling experimental result ItypevF/L, reported by Chandrasekhar et al. [Phys. Rev. Lett. 67, 3578 (1991)] for metallic rings of length L100l. If disorder is due to the grain boundaries, our data reproduce the theoretical result Ityp(evF/L)(l/L) that holds for the white-noise-like disorder and has been observed in recent experiments. Thus, result ItypevF/L in a disordered metallic ring of length Ll is as normal as result Ityp(evF/L)(l/L). Which result is observed depends on the nature of disorder. Experiments that would determine Ityp and l in correlation with the nature of disorder can be instructive.

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  • Received 28 March 2012

DOI:https://doi.org/10.1103/PhysRevB.88.125424

©2013 American Physical Society

Authors & Affiliations

J. Feilhauer and M. Moško*

  • Institute of Electrical Engineering, Slovak Academy of Sciences, 841 04 Bratislava, Slovakia

  • *martin.mosko@savba.sk

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Issue

Vol. 88, Iss. 12 — 15 September 2013

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