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Title:Quantum phenomena in disordered conductors
Author(s):Martin, Ivar
Director of Research:Phillips, Philip W.
Department / Program:Physics
Subject(s):disordered conductors
Kondo Effect
Abstract:In this thesis we consider three separate phenomena that arise in disordered conductors. The first part is devoted to the development of the theory of size and disorder dependence in the Kondo effect. We demonstrate that for a thin film of thickness L with mean-free path £, disorder provides a correction to the Kondo resistivity of the form T~ / (kFL£2 ) ln T that explains the disorder-induced depression of the Kondo effect observed experimentally in Cu(Fe) films. In the second part, we study the influence of non-magnetic transition element impurities on conventional superconductivity. We find that phonon coupling at impurities counteracts the traditional effects which dominate Tc suppression in the non-magnetic limit. In some cases, we predict that non-magnetic transition metal impurities can actually enhance Tc. We find qualitative agreement between the predicted increase and the experimental data for IV-VI degenerate semiconductors doped with Tl or In. In the third part, we present a simple qualitative model that interpolates between the high and low temperature properties of quasi-lD conductors. We argue that low-temperature transport is well described by localization theory, with a conductance that decays exponentially with the electron dephasing length. This model is shown to be in quantitative agreement with the experimental data on the organic conductor TTT2I3_8· We also show how the low-temperature positive magnetoresistance observed in TTT2 I3_ 8 and other quasi-lD conductors can be explained by the role spin-flip scattering plays in the electron dephasing rate.
Issue Date:2000
Genre:Dissertation / Thesis
Rights Information:© 1999 Ivar Martin
Date Available in IDEALS:2012-04-05

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