Addition spectra of quantum dots: the role of dielectric mismatch

Using atomistic pseudopotential wave functions we calculate the electron and hole charging energies of InAs quantum dots. We find that the charging energies depend strongly on the dielectric constant ǫout of the surrounding material, and that when the latter is smaller than the dielectric constant of the dot (weak external screening) the electron-electron and hole-hole interactions are dominated by surface polarization effects. We predict the addition energies and the quasi-particle gap as a function of size and ǫout. We find excellent agreement with recent single-dot tunneling spectroscopy data for ǫout = 6.