Observation of charging peaks near the flat band in magic-angle twisted bilayer Graphene*

Magic-angle twisted bilayer Graphene (MA-tBLG) has emerged as a highly tunable platform to study correlation physics. Numerous transport experiments have shown the existence of correlated insulating states, unconventional superconductivity and emergent ferromagnetism as the filling of the flat moire bands in MA-tBLG is tuned. More recently, several Scanning Tunneling Microscopy/Spectroscopy (STM/STS) experiments have also observed correlated-insulator like behavior, charge order and broken C3 symmetry in this system. Here, using Low temperature STM/STS measurements, we report the observation of sharp charging peaks which appear in the LDOS as the Fermi level is tuned close to the edges of the flat band. We perform a systematic study of these states to see their evolution in space using STS mapping. The observation of these states hints at the formation of local compressible regions surrounded by a gapped incompressible region because of tip induced band bending.