Spectroscopy of a single-carrier bilayer graphene quantum dot from time-resolved charge detection

Hadrien Duprez (ETH Zurich)

We measured the spectrum of a single-carrier bilayer graphene quantum dot as a function of both parallel and perpendicular magnetic field, using a time-resolved charge detection technique that gives access to individual tunnel events. Thanks to our energy resolution of 4 µeV, we could distinguish all four of the dot’s energy levels, in particular in the range of magnetic field where the first and second excited states cross (B⟂ ≲ 100 mT). We thereby experimentally establish the, hitherto simply extrapolated, single-charge carrier spectrum picture and provide a new upper bound for the inter-valley mixing, equal to our energy resolution.