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CoherentPotential Approximation for the Lattice Vibrations of Mixed III–V Crystals
Author(s) -
Kleinert P.
Publication year - 1984
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.2221220109
Subject(s) - lattice vibration , mixed mode , vibration , coherent potential approximation , lattice (music) , force constant , ion , mode (computer interface) , lattice constant , condensed matter physics , spectral line , crystal (programming language) , crystal system , physics , materials science , quantum mechanics , chemistry , crystal structure , phonon , crystallography , electronic structure , diffraction , computer science , molecule , acoustics , programming language , operating system , composite material
The coherentpotential approximation (CPA) is applied to the lattice dynamics of some III–V mixed crystals. The calculations are based on an eleven‐parameter rigid‐ion model (RIM 11). Explicit results are reported for the one‐mode system In 1− c Ga c P and the two mixed‐mode crystals In 1− c Ga c Sb and GaSb 1− c Ga c As c . Both, the reflectivity spectra and the composition dependence of vibrations at the Γ and X points are compared with existing experimental data. Force‐constant changes are considered by the virtual‐crystal approximation (VCA). The CPA theory is uniquely successful for III‐V mixed‐mode systems, which appear to switch from one‐mode to two‐mode behaviour.