Dynamical screening of the wannier exciton

Abstract

Abstract An effective mass equation for the Wannier exciton is derived with a, modified interaction taking dynamical screening due to unbound electron‐hole pairs into account. The binding energies are enhanced which distortes the hydrogenic series formula. In the limit of shallow excitons static screening is justified only in the dominant interaction term whereas the non‐Hermitean splitting terms are substantially affected. The connection with Haken's screening formula with regard to LO‐phonon screening is revealed.