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R. G. Herb Condensed Matter Seminar
Delocalization by disorder: non-metallic transport in layered metals
Date: Tuesday, October 20th
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Dmitrii Maslov, University of Florida
Abstract: Electron transport in many layered metals exhibits a number of puzzling anomalies: for example, while the temperature dependence of the in-plane resistivity is metallic, that of the out-of-plane resistivity is insulating or even non-monotonic. Also, it is often the case that the resistivity anisotropy cannot be accounted simply by mass anisotropy, which implies that disorder is strongly anisotropic as well. We show that, contrary to the widely accepted paradigm of "coherent-incoherent crossover", the Boltzmann equation is applicable to layered systems both for elastic and Eliashberg-type (dynamic) inelastic scattering as long as the "good-metal" condition (E_Fτ) is satisfied and disorder is not correlated. Therefore, a model containing only those sources of scattering cannot explain the experiment. We propose a model of two-channel transport, in which electrons propagate across the layers in two ways--coherently and via phonon-assisted tunneling through random resonant centers--and show how the experiment can be explained within this model. We also propose an explanation of anomalously large resistivity anisotropy in a model of two types of disorder: planar defects and isotropic impurities. We solve this model by mapping it onto the exact Berezinskii's solution of 1D localization problem and show that isotropic impurities destroy localization induced by planar defects.
Host: Andrey Chubukov
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