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

TL;DR

This paper presents an all-electrical method to prepare and detect many-particle spin states in self-assembled quantum dots, revealing detailed spectra and spin configurations of QD hydrogen, helium, and lithium at 4K.

Contribution

It introduces a novel electrical measurement technique for identifying and analyzing non-equilibrium many-particle spin states in quantum dots, supported by comparison with theoretical calculations.

Findings

Resolved pure-electron spectra of QD-hydrogen, helium, and lithium.

Identified singlet and triplet spin states in QD helium.

Demonstrated time-resolved evolution from non-equilibrium to equilibrium states.

Abstract

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.