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Raman scattering in CdGa 2 Se 4 under pressure
Author(s) -
Mitani T.,
Naitou T.,
Matsuishi K.,
Onari S.,
Allakhverdiev K.,
Gashimzade F.,
Kerimova T.
Publication year - 2003
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.200301579
Subject(s) - raman scattering , raman spectroscopy , tetragonal crystal system , phonon , phase transition , bulk modulus , materials science , bending , phase (matter) , lattice (music) , condensed matter physics , crystallography , chemistry , crystal structure , optics , physics , composite material , organic chemistry , acoustics
The Raman scattering spectra of CdGa 2 Se 4 under pressure were investigated at 300 K up to 20.9 GPa. TO as well as LO modes were observed. Two stages were observed in the pressure dependences of Raman bands. Such a behaviour was attributed to the ordedisorder phase transition in the cation sublattice. A first‐order phase transition under pressure was observed at 20.2 GPa. Using the HarrisoKeating model of the lattice dynamics modified for crystals with the tetragonal structure, the bulk modulus B and the mode‐Grüneisen parameters Γ i were determined for the first time. It is shown that a better agreement between the experimental and calculated values of Γ i is observed if one takes into consideration the different behaviour with pressure for the bond‐bending and the bond‐stretching parameters, which determine the low‐ (lower than 140 cm –1 ) and high‐ (higher than 140 cm –1 ) frequency phonons, respectively.
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