Stability of biexcitons in pyramidal InAs/GaAs quantum dots

Biexciton states in realistic quantum dots are investigated theoretically. The few-particle interactions are shown to depend sensitively on the struct ural, i.e. geometrical and chemical, properties of quantum dots. To investi gate the: interplay between the Coulomb and long-range exchange effects in the presence of correlation, we calculate the biexciton binding energy in p yramidal InAs/GaAs dots by configuration interaction, using realistic singl e-particle wavefunctions calculated including inhomogeneous strain, spin-or bit interaction, band mixing, and piezoelectricity. We show that both bindi ng or anti-binding biexciton ground states can occur in self-organized InAs /GaAs quantum dots, and that this is a generic property of the low symmetry of these dots.