Application of a Self Energy Approach for Calculation of Quasiparticle Energies in Semiconductor Superlattices

A unified theory of quasiparticle band energies based on first principles evaluation of the electron self energy operator including local fields in the screening of the Coulomb interaction as well as dynamical renormalization has been applied to the electronic structure of semiconductor superlattices. Two aspects of the problem are discussed. First, there is a substantial correction to the valence band offset calculated using the commonly applied local density functional approach. Second, the band structure of short period superlattices has been calculated directly for Si/Ge strained layer systems and the GaAs/AlAs system. The relative ordering of direct, pseudo-direct (folded) and indirect conduction bands is obtained from first principles.