Optical Spectra and Exciton in Correlated Insulators in Electron–Hole Systems

摘要: We study the optical properties of an electron–hole two-band Hubbard model with interactions electron–electron (hole–hole) repulsion U and attraction '. In case two types correlated insulators at half filling, viz. , Mott–Hubbard type biexciton type, interband linear absorption/gain spectra including excitonic effects are calculated analytically using two-site dynamical mean-field theory ladder approximation. show that exciton-like peak structure emerges because “exciton” in sea fermions when ' is larger than a certain critical value. The binding energy photoinduced bound state spectral intensity evaluated as function emergence absence suggests there different insulating mechanisms system: one attributable to only other both '; latter called t...