We review recent development in Raman techniques and diamond anvil cell technology, that allow measurements of Raman of metals in the megabar pressure range. The Raman technique includes holographic transmission optics and single-stage spectrographs with CCD array detectors. Use of synthetic high-purity diamonds and anglular excitation geometry reduces spurious background scattering substantially, which makes observable very weak Raman peaks in metals. We give several examples of studies including the hexagonal close packed (hcp) ϵ-Fe, Fe(1−x)Nix, and Re and the recently discovered high-temperature superconductor MgB2. The shift of phonon modes with pressure is used for determination of the mode-Gr\"uneisen parameters, estimation of shear elastic moduli and provide information on structural and electronic transitions.
@article{arxiv.cond-mat/0112404,
title = {Raman Scattering of Metals to Very High Pressures},
author = {Alexander F. Goncharov and Eugene Gregoryanz and Viktor V. Struzhkin and Russell J. Hemley and Ho-kwang Mao and Nabil Boctor and Eugene Huang},
journal= {arXiv preprint arXiv:cond-mat/0112404},
year = {2007}
}
Comments
18 pages, 10 figures, 2 tables, Proceedings of the International School of Physics "Enrico Fermi", Volume CXLVII, "High-Pressure Phenomena", edited by R. J. Hemley, M. Bernasconi, L. Ulivi and G. Chiarotti, in press