(UC Berkeley and Lawrence Berkeley National Lab)
GW-based Methods for ab initio Studies of Electronic Excited-State Phenomena in Condensed Matter
In this talk, we discuss recent progress in the use of the GW approach and its extensions to compute electronic excitations and related spectroscopic properties of materials and nanostructures. This interacting-electron Green’s approach incorporates many-electron interaction effects through the screened Coulomb interaction W. Inclusion of electron-hole interactions (excitonic effects) within the general framework moreover allows accurate ab initio study of optical responses and phenomena such as photo-induced structural changes. These many-electron effects are particularly important in reduced-dimensional systems and nanostructures, where symmetry, dimensionality and many-body interactions can lead to unusual manifestation of concepts/phenomena that may not be so prominent or have not been seen in bulk materials. Several phenomena are discussed, exploring their physical origin and comparing theoretical predictions with experimental data.