Coulomb-interaction-induced crossover from confined to bulk quantum-dot states in a magnetic field

We have employed inelastic light scattering to investigate electronic excitations of quantum dots in a magnetic field. For small magnetic fields the dispersion of the single-particle excitations (SPEs) follows the Fock–Darwin behavior. But already at moderate fields of B⩾0.6 T the SPEs deviate from that dispersion and follow directly the cyclotron resonance. This finding is explained by Coulomb-interaction-induced formation of bulk states in the center of the dot. Self-consistent ground-state calculations within the local-density approximation reproduce this result.