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Band tails in the density of states of mixed crystals
Author(s) -
Monecke J.
Publication year - 1989
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221520114
Subject(s) - density of states , gravitational singularity , percolation (cognitive psychology) , electronic band structure , binary number , condensed matter physics , class (philosophy) , percolation theory , physics , quantum mechanics , theoretical physics , statistical physics , mathematics , conductivity , arithmetic , neuroscience , biology , artificial intelligence , computer science
The Saxon‐Hutner theorem proves the existence of band tails in the density of states for a wide class of models of mixed crystals. These band tails are discussed in detail by Lifshitz. They are not obtained, however, in self‐consistent theories like the coheren, potential approximation or in the theory of Klauder. The non‐existence of band tails in the self‐consistent theories is related to a wrong percolation behaviour of the self‐energy and it is proved that a recently proposed alternative theory results in a density of states which fulfils the Saxon‐Hutner theorem. Further it is shown that the density of states of binary mixed crystals exhibits all Van Hove singularities of both pure constituents.