RELATIVE IMPORTANCE OF SELF-CONSISTENCY AND VARIABLE SYMMETRY IN THE CALCULATION OF EXCITON ENERGIES IN TYPE-I AND TYPE-II SEMICONDUCTOR HETEROSTRUCTURES

We investigate, in a self-consistent manner, the effects of the Coulom bic interaction on the electron and hole wave functions of an exciton in a quantum-well structure. The method developed includes a dimension ality parameter which allows the relative motion term in the exciton w ave function to assume two-dimensional, three-dimensional, or any inte rmediate symmetry should it be energetically favorable to do so. The r esults are compared with those obtained using either a two- or three-d imensional form for the relative motion. A study of the magnetic held induced type-I-type-II transition in diluted magnetic semiconductors s hows that the inclusion of self-consistency is essential to an underst anding of the optical properties of quantum-well structures with flat or type-II valence-band alignments. A. comparison with observations of this phenomenon is given.