Abstract
Typical persistent current () 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 () is determined. If disorder is due to the rough edges, a ballistic persistent current is found to coexist with the diffusive resistance (), where is the Fermi velocity and 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 , reported by Chandrasekhar et al. [Phys. Rev. Lett. 67, 3578 (1991)] for metallic rings of length . If disorder is due to the grain boundaries, our data reproduce the theoretical result that holds for the white-noise-like disorder and has been observed in recent experiments. Thus, result in a disordered metallic ring of length is as normal as result . Which result is observed depends on the nature of disorder. Experiments that would determine and in correlation with the nature of disorder can be instructive.
6 More- Received 28 March 2012
DOI:https://doi.org/10.1103/PhysRevB.88.125424
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