Quantum-dot ground states in a magnetic field studied by single-electron tunneling spectroscopy on double-barrier heterostructures

The few-electron ground states of a strongly asymmetric nanometer-scale ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As-GaAs double-barrier quantum dot are probed by single-electron tunneling spectroscopy. Magnetotunneling measurements reveal transitions of spin and orbital angular momentum of the two- and three-electron quantum-dot ground states, respectively. The experimental data are compared with exact calculations of the few-electron ground-state energies. Magnetic-field-induced modulations of the tunneling rate in the many-electron regime indicate correlations in the involved states.