SELF-CONSISTENT CALCULATIONS OF QUASIPARTICLE STATES IN METALS AND SEMICONDUCTORS

We solve the Dyson equation for the one-particle Green{close_quote}s function in a periodic solid self-consistently within the shielded-interaction (or GW ) approximation. The effect of self-consistency (propagator renormalization) is found to be substantial. We illustrate this finding via calculations of quasiparticle states in K and Si. In the case of Si we show that the current standard of {ital ab initio} quasiparticle theory, the GW self-energy diagram, fails to account for the observed value of the absolute band gap{emdash}if properly, i.e., self-consistently, evaluated. {copyright} {ital 1998} {ital The American Physical Society }