Abstract
A novel picture of the quasiparticle (QP) gap in prototype semiconductors Si and Ge emerges from an analysis based on all-electron, self-consistent, GW calculations. The deep-core electrons are shown to play a key role via the exchange diagram—if this effect is neglected, Si becomes a semimetal. Contrary to current lore, the Ge semicore states (e.g., their polarization) have no impact on the GW gap. Self-consistency improves the calculated gaps—a first clear-cut success story for the Baym-Kadanoff method in the study of real-materials spectroscopy; it also has a significant impact on the QP lifetimes. Our results embody a new paradigm for ab initio QP theory.
- Received 11 January 2002
DOI:https://doi.org/10.1103/PhysRevLett.89.126401
©2002 American Physical Society