The violation of the Hund rule in semiconductor artificial atoms

Abstract

The unrestricted Pople–Nesbet approach for real atoms is adapted to quantum dots under applied magnetic field. Gaussian basis sets are used instead of the exact single-particle orbitals in the construction of the appropriated Slater determinants. Both system chemical potential and charging energy are calculated, as well as the expected values for total spin and its z-component. We have verified the validity of the energy shell structure as well as the Hund rule for state population at zero magnetic field. Above given fields, we have observed a violation of the Hund rule by the suppression of triplet and quartet states at the 1p-energy shell, taken as an example. We have also compared our present results with those obtained by using the LS-coupling scheme for low electronic occupations. We have focused our attention on ground-state properties of GaAs quantum dots populated up to 40 electrons.