Understanding nanoscale energy dissipation is nowadays among few priorities in solid state systems. Pendulum geometry Atomic Force Microscope (pAFM), oscillating like a tiny pendulum over the surface, is perfectly suited to measure minute energy loss.
Here we report on low temperature energy dissipation measurements on twisted bilayer graphene (TBG) at magic angle twist - a system with flat electronic bands and highly correlated insulating phases. pAFM showed giant dissipation peaks attributed to different electron/hole filling of the flat band. The pAFM imaging allows to map the twist angle distribution of TBG. Application of magnetic fields provoked strong quantum oscillations of the dissipation signal which is enhanced for fractional band filling.