THE DENSITY OF STATES OF A SPATIALLY DISORDERED TIGHT-BINDING MODEL
We give an exact analysis of the configurationally averaged Green functions for a random tight-binding model characterised by quenched liquíd-like disorder, using a graph-theoretical method originally applied by Wertheim to a problem in classical dielectric theory. The structural characteristics of...
| Main Authors: | , |
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| Formato: | Journal article |
| Idioma: | English |
| Publicado em: |
1988
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| Resumo: | We give an exact analysis of the configurationally averaged Green functions for a random tight-binding model characterised by quenched liquíd-like disorder, using a graph-theoretical method originally applied by Wertheim to a problem in classical dielectric theory. The structural characteristics of the system are incorporated fully. We derive a formally exact self-consistency equation for the averaged diagonal Green function Ḡ(z), from which follows the density of states. A systematic derivation and critical discussion of various approximate theories for Ḡ(z) is given. We also show that extension to include site-diagonal disorder is straightforward for single-site theories. Finally, an illustrative calculation of the density of states is carried out for the low-density domain. © 1988 IOP Publishing Ltd. |
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