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

Abstract

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 ∼ 30 Å)is calculated using pseudopotential single-particle energies and wave functions as input to the many-body expansion of the total energy.The validity of generally accepted “rules of level occupation”(Hund's rule, Aufbau principle, and single spin-flip rule) is examined. We find that while Hund's rule is generally obeyed,deviations from the Aufbau principle are common when single-particle energy levels are separated by a few meV. We also finda few instances where the single spin-flip rule is violated,leading to “spin blockade” in linear conductance.