Anharmonic line shift and linewidth of the Raman mode in covalent semiconductors

Combining density-functional perturbation theory with the frozen-phonon app roach, the anharmonic shift of the Raman frequency of the covalent semicond uctors diamond and silicon are determined ab initio. The temperature depend ence of the Raman frequency and the contribution of zero-point motion are c alculated as well as the Raman linewidth. Corresponding results for germani um have been obtained with the assumption that the quartic anharmonic force constants may be approximated by those of silicon. [S0163-1829(99)13305-8] .