EFFECT OF EXCITON-OPTICAL PHONON INTERACTIONS ON THE BINDING-ENERGIESOF EXCITONS IN IONIC QUANTUM-WELL STRUCTURES

We have derived an expression for the effective interaction potential between the constituents of an exciton, namely an electron and a hole in an ionic quantum well structure by taking into account the electron -hole interactions with the confined optical, interface and half-space longitudinal optical phonon modes using a variational method. We foll ow an approach similar to that used by Haken to derive an effective po tential between an electron and a hole in bulk ionic crystals. Using o ur interaction potential we have calculated the binding energies of ex citons in several ionic quantum well structures. We find that the valu es of the exciton binding energies calculated using this effective int eraction potential are always larger than those obtained using a Coulo mb potential screened by the static dielectric constant. We compare ou r results with those of some recent calculations.