Effects of pressure on the phonon-phonon and electron-phonon interactions in semiconductors

We discuss the dependence of phonon frequencies on hydrostatic pressure for tetrahedrally bonded semiconductors, in particular the linear term represented by mode Gruneisen parameters. The relation between these parameters and the thermal expansion is also elucidated. Emphasis is placed on recent results that concern the zero-point renormalization of lattice parameters and its dependence on isotopic masses. The pressure dependence of transverse charges of ir-active phonons is also touched upon. We also discuss strong pressure and isotopic mass effects on phonon widths and line shapes that are occasionally observed for selected materials. Finally, we present recently observed effects of pressure on the luminescence of isotopically pure silicon which are strong enough to be easily detected in the 0-1 bar range. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.