We investigate the influence of electron-electron interactions on the electronic properties of quantum dots in a regime where the energy-level separation is comparable to or larger than the Coulomb charging energy at low temperature ${(e}^2/2C\gg k_{B}T).\mathrm{}$ A self-consistent three-dimensional solution of Schrödinger and Poisson equation within the local-density approximation is implemented to study the formation of shell structure in highly symmetric quantum dots which is in good agreement with recent experimental results [Tarucha et al., Phys. Rev. Lett. 77, 3613 (1996)] For asymmetric quantum dots, we show that the shell structure disappears, and features due to electron-electron interaction lead to the accidental formation of an isolated electron shell called “Coulomb degeneracy” in the energy spectrum.

• Received 17 March 1997

DOI:https://doi.org/10.1103/PhysRevB.56.15752