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VOLUME 50 (1989) | ISSUE 3 |
PAGE 116
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Equation of state and Raman scattering in cubic BN and SiC at high pressures
Aleksandrov I. V. , Goncharov A. F. , Stishov S. M. , Yakovenko E. V.
The results of simultaneous measurements of first-order Raman spectra and the lattice parameter of cubic BN and SiC at pressures of up to 34 and 42.5 GPa are presented. The bulk moduli and their pressure derivatives at Ρ = 0, and also the volume dependences of the Gruneisen parameters of the LTO (Γ) modes have been determined. The "average"11 Gruneisen parameter, fLTo > of boron nitride is found to remain essentially constant upon compression. In contrast, the Gruneisen parameter of silicon carbide, yLXO, decreases as a result of the application of pressure. A correlation is established between the electronic structure of the ion cores and the behavior of the optical modes under pressure in C, BN, SiC, and Si.
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