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Effect of Pressure on the Anomalous Raman Spectrum of CuBr
Author(s) -
Manjón F.J.,
Serrano J.,
Loa I.,
Syassen K.,
Lin C.T.,
Cardona M.
Publication year - 2001
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 - 10.1002/1521-3951(200101)223:1<331::aid-pssb331>3.0.co;2-e
Subject(s) - laser linewidth , anharmonicity , phonon , raman spectroscopy , hydrostatic pressure , condensed matter physics , raman scattering , anomaly (physics) , chemistry , ambient pressure , spectral line , optics , physics , laser , astronomy , thermodynamics
Raman spectra of isotopically pure zinc‐blende CuBr ( 63 Cu 81 Br) were measured at T = 10 K under hydrostatic pressures up to 4 GPa. The ambient‐pressure spectrum consists of a transverse‐optic (TO) phonon line and an anomalous broad band located at frequencies near the expected first‐order longitudinal‐optic (LO) scattering. Application of hydrostatic pressure leads to an increase of the linewidth of the TO mode and to a significant change of the LO scattering band which above 3 GPa develops into a single LO phonon peak of narrow linewidth. The disappearance of the LO Raman anomaly as well as the broadening of the TO mode with pressure are explained by pressure‐dependent third‐order anharmonic interactions of zone‐center optical phonons with q = 0 two‐phonon states.