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RESEARCH PRODUCT
Raman Scattering in CuCl under Pressure
Clemens UlrichA. GbelManuel CardonaAna CrosK. SyassenAndrés Cantarerosubject
Condensed matter physicsChemistryPhononCondensed Matter PhysicsMolecular physicsElectronic Optical and Magnetic MaterialsCondensed Matter::Materials Sciencesymbols.namesakeX-ray Raman scatteringDispersion relationMolecular vibrationsymbolsCondensed Matter::Strongly Correlated ElectronsCoherent anti-Stokes Raman spectroscopyFermi resonanceRaman spectroscopyRaman scatteringdescription
Raman spectra of CuCl were measured under hydrostatic pressures up to 14 GPa at low temperatures (T = 5 K). The anomaly in the Raman lineshape of zincblende CuCl at frequencies near the transverse-optic (TO) mode, which consists of a broad structure with several maxima, disappears at a pressure near 3 GPa. This effect is well reproduced by a model calculation of the anharmonic coupling of the TO mode to acoustic two-phonon states (Fermi resonance). Alternative interpretations of the TO Raman anomaly in terms of local vibrational modes of Cu atoms in off-center positions are not supported by the present results. Raman spectra indicate the existence of the phase CuCl-IIa in a narrow pressure range (3.3 and 4.1 GPa). Based on calculated phonon dispersion relations we propose an assignment for the Raman modes observed for the binary BC8-analog phase CuCl-IV in the range from 4.1 to 14 GPa.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1999-01-01 | physica status solidi (b) |