We consider circular and elliptic quantum dots with parabolic external confinement, containing 0–22 electrons and with values of $r_s$ in the range $0<r_s<3$. We perform restricted and unrestricted Hartree-Fock calculations, and further take into account electron correlations using second-order perturbation theory. We demonstrate that in many cases correlations qualitatively change the spin structure of the ground state from that obtained under Hartree-Fock and spin-density-functional calculations. In some cases the correlation effects destroy Hund’s rule. We also demonstrate that the correlations destroy static spin-density waves observed in Hartree-Fock and spin-density-functional calculations.

• Received 18 August 2004

DOI:https://doi.org/10.1103/PhysRevB.71.235326