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Ultrasonic attenuation in strongly disordered electronic systems

Kotliar, B Gabriel and Ramakrishnan, TV (1985) Ultrasonic attenuation in strongly disordered electronic systems. In: Physical Review B, 31 (12). 8188 -8195.

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Official URL: http://prola.aps.org/abstract/PRB/v31/i12/p8188_1


The attenuation of long-wavelength phonons due to their interaction with electronic excitations in disordered systems is investigated here. Lattice strain couples to electronic stress, and thus ultrasonic attenuation measures electronic viscosity. The enhancement and critical divergence of electronic viscosity due to localization effects is calculated for the first time. Experimental consequences for the anomalous increase of ultrasonic attenuation in disordered metals close to the metal-insulator transition are discussed. In the localized regime, the appropriate model is one of electronic two-level systems (TLS’s) coupled to phonons. The TLS consists of a pair of states with one localized state occupied and the other unoccupied. The density of such low-excitation-energy TLS’s is nonzero due to long-range Coulomb interactions. The question of whether these could be significant low-energy excitations in glasses is touched upon.

Item Type: Journal Article
Publication: Physical Review B
Publisher: The American Physical Society
Additional Information: The copyright of this article belongs to The American Physical Society.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 24 Nov 2009 09:23
Last Modified: 19 Sep 2010 05:35
URI: http://eprints.iisc.ac.in/id/eprint/20945

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