Saddle-point excitons in solids and superlattices

Abstract
A new method has been developed to study saddle-point excitons in solids and semiconductor superlattices. Interband absorption spectra of solids within simple tight-binding models are calculated with the inclusion of the electron-hole Coulomb interaction. Absorption spectra associated with saddle-point exciton resonances in superlattices are also studied as functions of the layer thickness.