Hund's rule, spin blockade, and the Aufbau principle in strongly confined semiconductor quantum dots

The ground-state configuration of a system of N electrons or holes (N = 1 . .. 8) in strongly confined InAs, InP, and Si quantum dots (diameter similar to 30 Angstrom) is calculated using pseudopotential single-particle energi es and wave functions as input to the many-body expansion of the total ener gy. The validity of generally accepted "rules of level occupation" (Hund's rule, Aufbau principle, and single spin-flip rule) is examined. We find tha t while Hund's rule is generally obeyed, deviations from the Aufbau princip le are common when single-particle energy levels are separated by a few meV . We also find a few instances where the single spin-flip rule is violated, leading to "spin blockade" in linear conductance.