Abstract:

With far-infrared spectroscopy, coupling between electron quantum dots becomes visible in the electronic excitation spectrum. We employ gated GaAs-AlGaAs quantum wells that enable field-effect tuning of the coupling between adjacent dots. For noninteracting quantum dots in a magnetic field we observe the characteristic edge- and bulk-mode spectrum.. The coupling of dots is reflected by a branching of the bulk mode into a cyclotron-resonance-like and a magnetoplasmonlike mode and a splitting of the edge mode. The latter is caused by formation of new edge orbits embracing two adjacent dots.