Addition spectra of quantum dots: The role of dielectric mismatch

TL;DR

This paper investigates how dielectric mismatch influences the addition spectra of InAs quantum dots, revealing the significant role of surface polarization effects on charging energies and matching experimental data.

Contribution

It introduces atomistic pseudopotential calculations to quantify dielectric effects on quantum dot charging energies, highlighting the importance of surface polarization.

Findings

Charging energies depend strongly on surrounding dielectric constant

Surface polarization effects dominate when epsilon_out is smaller than the dot's dielectric constant

Predicted addition energies align with experimental tunneling spectroscopy data

Abstract

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 epsilon_out of the surrounding material, and that when the latter is smaller than the dielectric constant of the dot 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 epsilon_out. We find excellent agreement with recent single-dot tunneling spectroscopy data for epsilon_out=6.