Pressure dependence of Raman Linewidth in semiconductors

Abstract

The pressure dependences of the phonon lifetimes of zone-center optical phonons of various group IV and III-V semiconductors are calculated from first principles using third-order density-functional perturbation theory. The microscopic mechanism responsible, i.e. the anharmonic decay of a phonon into phonons of different energy, is revealed and the sensitive dependence on pressure is studied in detail. The results are compared with recent measurements of the pressure dependence of the linewidths of the first order Raman lines of Si, Ge, and SiC.