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oai:uvadoc.uva.es:10324/653322025-02-13T09:51:34Zcom_10324_1158com_10324_931com_10324_894col_10324_1242

00925njm 22002777a 4500 dc Tallman, R. E. author Cantarero, A. author Garro, N. author Lauck, R. author Ritter, T. M. author Weinstein, B. A. author Cardona, M. author Serrano Gutiérrez, Jorge author 2004 Pressure-Raman studies (to 15 GPa, at 300 K and 16 K) are reported on 64Zn34S, 68Zn32S, and natural ZnS to compare the effects of resonant 3-phonon mixing on the TO(Γ) phonons for the different isotope compositions. Under pressure the TO(Γ) Raman profiles exhibit several distinct features, and a sharp Lorentzian TO(Γ) peak eventually emerges at a threshold pressure PTh that differs for each isotope composition. These effects are due to resonant mixing of the TO(Γ) phonon with TA + LA combination modes. Calculations based on a bond-charge model and perturbation theory reproduce the observed pressure variations in the shape and the width of the TO(Γ) peaks. It is shown that these changes relate to singularities in the TA + LA density of states. Mass scaling of the TO(Γ) and TA + LA modes explains the isotope effect on PTh, and leads to the estimate γLA(W) ∼1.2 phys. stat. sol. (b) 241, No. 14, 3143 – 3148 (2004) 0370-1972 https://uvadoc.uva.es/handle/10324/65332 10.1002/pssb.200405221 3143 14 3148 physica status solidi (b) 241 1521-3951 Pressure‐Raman study of resonant TO(Γ)–two‐phonon decay processes in ZnS: Comparison of three isotope compositions