MANY-BODY EFFECT IN AN ARTIFICIAL ATOM

Atomic-like properties of vertical quantum dots are studied by measuri ng Coulomb oscillations. The Coulomb oscillations in the linear transp ort regime become irregular in period, reflecting a shell structure an d the obedience to Hund's rule, as the number of electrons in the dot approaches zero. Under a high magnetic field, many-body effects become important, and we observe kink structures in the few-electron regime in the Coulomb oscillation peak positions versus the magnetic field. T he kink structures are well assigned to transition in spin and angular momentum states, which we predict by the exact diagonalization approa ch. (C) 1998 Elsevier Science B.V. All rights reserved.