Fine structure of localized exciton levels in quantum wells

A theory is constructed for the long-range exchange and retarding interactions between an electron and a hole in a quantum well. A method is developed that makes it possible to calculate the ground and excited states of an exciton localized as a whole on a width fluctuation of a quantum well in the form of a rectangular island. It is shown that taking into account the electron-hole interaction mechanisms considered here causes the radiation doublet of the exciton to split into two components polarized along the sides of the rectangle. The dependence of the magnitude and sign of this splitting on the linear dimensions of the island and the level number of the localized exciton are analyzed.