Ab initiocalculation of the low-frequency Raman cross section in silicon

The macroscopic polarizability of silicon is calculated from first principles as a function of the lattice distortion induced by a zone-center optical phonon. The electronic response to the electric field is dealt with by dielectric matrices, and the lattice distortion is treated by frozen-phonon techniques. Our results compare quite well with the most recent measurements of the one-phonon Raman cross section.