SPECTRAL PROPERTIES OF QUASI-PARTICLES IN A SEMICONDUCTOR

The one-electron excitation spectrum of the prototype semiconductor Si has been obtained from a first principles calculation of the spectral -weight function A((q) over right arrow, omega) of the interacting one -electron Green's function. The Dyson equation has been solved with th e self-energy operator obtained in the GW approximation, where the bar e propagator G and the omega-dependent screening matrix W, without (ra ndom-phase approximation) and with (time-dependent local density appro ximation) vertex corrections, have been computed within Kohn-Sham-loca l-density-approximation theory. Positions of quasiparticle peaks (i.e. , the ''band structure''), their lifetimes, and satellite (plasmaron) spectral structures are extracted in a broad energy range. [S0163-1829 (97)08140-X].