First-excited-state energy of hydrogenic impurity bound polaron in an anisotropic quantum dot in an electric field

The first-excited-state (ES) binding energy of hydrogenic impurity bound polaron in an anisotropic quantum dot (QD) is obtained by constructing a variational wavefunction under the action of a uniform external electric field. As for a comparison, the ground-state (GS) binding energy of the system is also included. We apply numerical calculations to KBr QD with stronger electron–phonon (E–P) interaction in which the new variational wavefunction is adopted. We analyzed specifically the effects of electric field and the effects of both the position of the impurity and confinement lengths in the xy-plane and the [Formula: see text] direction on the ground and the first-ES binding energies (BEs). The results show that the selected trial wavefunction in the ES is appropriate and effective for the current research system.

Hydrogenic impurity bound polaron in an anisotropic quantum dot

The effect of the electron–phonon interaction on an electron bound to a hydrogenic impurity in a three-dimensional (3D) anisotropic quantum dot (QD) is studied theoretically. We use the Landau–Pekar variational approach to calculate the binding energy of ground state (GS) and first-excited state (ES) with considering electron–phonon interaction. The expressions of the GS and ES energies under investigation depict a rich variety of dependent relationship with the variational parameters in three different limiting cases. Numerical calculations were performed for ZnSe QDs with different confinement lengths in the xy-plane and the z-direction, respectively. It is illustrated that binding energies of impurity polarons corresponding to each level are larger in small QDs. Furthermore, the contribution to binding energy from phonon is about 15% of the total binding energy.