Effect of pressure on the Raman anomaly of zinc-blende CuBr and Raman spectra of high-pressure phases
Raman spectra of isotopically pure CuBr (63Cu81Br) were measured under hydrostatic pressures up to 10 GPa at 10 K. The anomalous line shape of the longitudinal-optic (LO) scattering in the zinc-blende phase (CuBr-III, 0–4 GPa), consisting of a broad structure between 155 and 177cm−1, exhibits a cont...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2001 |
| País: | España |
| Institución: | Universidad de Valladolid |
| Repositorio: | UVaDOC. Repositorio Documental de la Universidad de Valladolid |
| OAI Identifier: | oai:uvadoc.uva.es:10324/65356 |
| Acceso en línea: | https://doi.org/10.1103/PhysRevB.64.064301 https://uvadoc.uva.es/handle/10324/65356 |
| Access Level: | acceso abierto |
| Sumario: | Raman spectra of isotopically pure CuBr (63Cu81Br) were measured under hydrostatic pressures up to 10 GPa at 10 K. The anomalous line shape of the longitudinal-optic (LO) scattering in the zinc-blende phase (CuBr-III, 0–4 GPa), consisting of a broad structure between 155 and 177cm−1, exhibits a continuous change with pressure and develops into a narrow LO phonon peak near 4 GPa. The disappearance of the LO Raman anomaly as well as the pronounced broadening of the TO mode with pressure are explained in terms of pressure-dependent third-order anharmonic interactions with two-phonon states. A Fermi resonance model, which is based on a shell model fit of available phonon dispersion data, fully accounts for the changes in Raman line shapes under pressure. Low-temperature Raman spectra of the tetragonal CuBr-IV and cubic CuBr-V high-pressure phases are also reported. An assignment of the observed Raman modes of these phases is proposed. |
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