Stability of the shell structure in 2D quantum dots

TL;DR

This paper investigates how external impurities affect the shell structure in 2D quantum dots, revealing that shell integrity remains largely intact despite high disorder, with Coulomb interactions significantly influencing energy distributions.

Contribution

It introduces a fast response-function method to analyze the stability of shell structures in disordered quantum dots with multiple electrons.

Findings

Shell structure is generally preserved despite high disorder.

Coulomb interactions significantly affect addition-energy distributions.

Ground-state spin variations influence energy level statistics.

Abstract

We study the effects of external impurities on the shell structure in semiconductor quantum dots by using a fast response-function method for solving the Kohn-Sham equations. We perform statistics of the addition energies up to 20 interacting electrons. The results show that the shell structure is generally preserved even if effects of high disorder are clear. The Coulomb interaction and the variation in ground-state spins have a strong effect on the addition-energy distributions, which in the noninteracting single-electron picture correspond to level statistics showing mixtures of Poisson and Wigner forms.