The Interaction of Surface Excitons

Abstract

Abstract The Fourier transform v ( p ) of the exciton–exciton interaction energy is derived. The excitons are situated in a semiinfinite polar crystal near the surface. The character of the interaction depends essentially on the symmetry of the spin functions under the permutation of identical particles. On the base of v ( p ) the shift of the surface excitons level with increasing exciton density n ex is obtained. The numerical value is listed for GaAs. The effective Hamiltonian of surface excitons interacting through exchange by virtual surface longitudinal optical phonons is derived.