Non-equilibrium many-particle spin states in self-assembled quantum dot hydrogen, helium and lithium

We introduce an all-electrical measurement technique, which makes it possible to prepare and detect the ground and excited many-particle states in self-assembled InAs QDs at 4K. This way, the pure-electron spectra of QD-hydrogen, -helium and -lithium are resolved. Comparison with detailed many-body calculations enables us to identify the different charge configurations and in particular detect the singlet and triplet spin states of QD helium. Furthermore, the time-resolved evolution of the density of states from non-equilibrium to equilibrium charge occupation is shown.