Phonon Raman scattering from slightly overdoped (Formula presented) samples have been investigated under hydrostatic pressure up to 7.2 GPa. Although most observed phonons harden linearly with increasing pressure, the (Formula presented)-type Cu mode at 140 (Formula presented) exhibits a nonlinear hardening with an inflection point around 2 GPa, similar to the dependence of (Formula presented) versus pressure. We also find that the mode-specific Grüneisen parameters scale inversely with the corresponding vibrational frequencies, a trend similar to what is observed for molecular solids. The data are interpreted in terms of a nonuniform structural compressibility that results in a redistribution of charge carriers within the (Formula presented) unit cell.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics