Noninvasive detection of molecular bonds in quantum dots

We performed charge detection on a lateral triple quantum dot with starlike geometry. The setup allows us to interpret the results in terms of two double dots with one common dot. One double dot features weak tunnel coupling and can be understood with atomlike electronic states, the other one is strongly coupled forming moleculelike states. In nonlinear measurements we identified patterns that can be analyzed in terms of the symmetry of tunneling rates. Those patterns strongly depend on the strength of interdot tunnel coupling and are completely different for atomiclike or moleculelike coupled quantum dots allowing the noninvasive detection of molecular bonds.