Stability of Biexcitons in Pyramidal InAs/GaAs Quantum Dots

Abstract

Biexciton states in realistic quantum dots are investigated theoretically. The few-particle interactions are shown to depend sensitively on the structural, i.e. geometrical and chemical, properties of quantum dots. To investigate the interplay between the Coulomb and long-range exchange effects in the presence of correlation, we calculate the biexciton binding energy in pyramidal InAs/GaAs dots by configuration interaction, using realistic single-particle wavefunctions calculated including inhomogeneous strain, spin–orbit interaction, band mixing, and piezoelectricity. We show that both binding 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.