A spin-polarized bi-exciton in a semiconductor quantum dot

Abstract

We discuss the role of spin-polarized multi-exciton complexes in the emission spectra ofsemiconductor quantum dots. The spin-polarized bi-exciton complex composed of twospin-polarized electrons and two spin-polarized holes confined in a single, parabolic,self-assembled quantum dot is discussed in detail. The configuration-interaction approach isused to compute the energies, wavefunctions, and emission spectra as a function of themagnetic field. It is shown that the spin-polarized bi-exciton emission spectrumdiffers from the unpolarized spectrum due to the Pauli blocking and exchangeinteractions. The emission from spin-polarized bi-exciton allows for the measurement ofground and excited single-exciton states, and its magnetic field dependence allowsfor the differentiation of the spin-polarized bi-exciton and tri-exciton spectrum.