Abstract
Pressure-induced phase transitions of lead chalcogenides were studied by Raman spectroscopy. The number of Raman modes observed for the first high-pressure phases was found to be significantly less than expected from selection rules for the proposed GeS-type orthorhombic structure. The observations are consistent with the alternative assignment as CrB-type. In the case of PbS, the disappearance of the intermediate-phase Raman lines in the pressure range of 19–25 GPa, i.e., in the vicinity of the orthorhombic to CsCl-type phase transition, is accompanied by a strong increase in a structureless background. The Raman background is attributed to light scattering by charge carriers in the metallic CsCl-type phase.
†This paper was presented at the XLVIth European High Pressure Research Group (EHPRG 46) Meeting, Valencia (Spain), 7–12 September, 2008.
Acknowledgements
The work was supported by the Russian Foundation for Basic Research (Grant no. 05-02-16780, 08-02-00437 and 07-08-00338). Yu.S.P. acknowledges support by the Max-Planck Society.
Notes
†This paper was presented at the XLVIth European High Pressure Research Group (EHPRG 46) Meeting, Valencia (Spain), 7–12 September, 2008.