Optical properties of two-electron quantum dots in low lying para- and ortho-states

Two low lying energy levels of 3D two-electron quantum dot with rigid confinement (the wave functions vanish at the surface of the quantum dot) are obtained by the variational and perturbation methods. There are two kind of quantum dots: para- and ortho-dots with antiparallel and parallel electron spins, respectively. An ensemble of the two-electron quantum dots contains para-dots in the ground state and ortho-dots in the lowest metastable state at low enough temperatures. The optical parameters of GaAs two-electron quantum dot are calculated with the help of obtained energy levels and compared with the optical parameters known for the one electron GaAs quantum dot. The Coulomb interaction between electrons is responsible for the blue shift of maxima of the absorption coefficient and refractive index of two-electron quantum dots.

► The first two low lying energy levels of two electron quantum dots are calculated. ► There are two types of quantum dots: para- and ortho-quantum dots. ► Para- and one of the non-factorizable ortho-state of the dot relate to EPR-state. ► The maxima of optical quantities show blue shift due to the Coulomb interaction.