Premium
Cluster approximation for the spectral density of mixed diatomic systems
Author(s) -
Kleinert P.
Publication year - 1979
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.2220910211
Subject(s) - diatomic molecule , cluster (spacecraft) , impurity , range (aeronautics) , molecular physics , physics , spectrum (functional analysis) , condensed matter physics , density of states , atomic physics , chemistry , materials science , quantum mechanics , molecule , computer science , composite material , programming language
The spectral density of a mixed diatomic linear chain is investigated using the truncated‐ T ‐matrix approximation of Berk et al. Only the mass disorder is taken into account. If above the maximum host crystal frequency an impurity band exists then there occur remarkable differences between the cluster and CPA spectrum. In this frequency region the cluster results show some fine structures, which are investigated in dependence on the concentration of the impurities and on a short range order parameter, respectively. A not very pronounced fine structure occurs also between the acoustic and optic band if gap modes exist.