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Zone‐centered phonons in A I B III S 2 chalcopyrites
Author(s) -
Koschel W. H.,
Bettini M.
Publication year - 1975
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.2220720233
Subject(s) - phonon , raman spectroscopy , bond length , condensed matter physics , physics , yield (engineering) , spectral line , raman scattering , homopolar motor , atomic physics , molecular physics , crystallography , chemistry , optics , crystal structure , quantum mechanics , thermodynamics , magnet
The spectra of the zone‐centered phonons in five compounds of the A I B III S 2 chalcopyrite (ch) family are completed by IR absorption and Raman scattering measurements. The ch extended Keating model is applied to these phonons. The experiments and calculations clarify the assignments of the Γ 3 ‐modes and the low‐energy modes which originate from the transverse acoustic zincblende (zb) phonons. The central force constants between nearest neighbours α BS of the homopolar bonds are very large corresponding to the small bond lengths. On the other hand, the strong heteropolar A–S bonds yield very low α AS ‐values. The model parameters, which are determined by optical phonon fitting, also reproduce in a zb approximation the elastic moduli of AgGaS 2 .