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Singular Effect of Disorder on Electronic Transport in Strong Coupling Electron-Phonon Systems

Sanjeev Kumar·Pinaki Majumdar
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Abstract

We solve the disordered Holstein model in three dimensions considering the phonon variables to be classical. After mapping out the phases of the `clean' strong coupling problem, we focus on the effect of disorder at strong electron-phonon (EP) coupling. The presence of even weak disorder (i) enormously enhances the resistivity (ρ) at T=0, simultaneously suppressing the density of states at the Fermi level, (ii) suppresses the temperature dependent increase of ρ, and (iii) leads to a regime with dρ/dT <0. We locate the origin of these anomalies in the disorder induced tendency towards polaron formation, and the associated suppression in effective carrier density and mobility. These results, explicitly at `metallic' density, are of direct relevance to disordered EP materials like covalent semiconductors, the manganites, and to anomalous transport in the A-15 compounds.

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Sanjeev Kumar, Pinaki Majumdar. 2005-04-17. Singular Effect of Disorder on Electronic Transport in Strong Coupling Electron-Phonon Systems. https://doi.org/10.1103/physrevlett.94.136601

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