Electron and hole addition energies in PbSe quantum dots

We calculate electron and hole addition energies of PbSe quantum dots using a pseudopotential configuration-interaction approach. We find that (i) the addition energies are nearly constant for the first eight carriers occupying the $S$-like shell. (ii) The charging sequence of the first eight carriers is non-Aufbau, but filling of the $P$-like single-particle states takes place only after the $S$-like states are filled. (iii) The charging spectrum shows bunching-up of all lines as the dielectric constant ${\epsilon }_{\text{out}}$ of the material surrounding the dot increases. At the same time, the addition energies are significantly reduced. (iv) The calculated optical gap shows a rather weak dependence on ${\epsilon }_{\text{out}}$, reflecting a cancellation between electron-hole interaction energies and surface polarization self-energies.