We use spatially-resolved angle-resolved photoemission spectroscopy (µ-ARPES) to probe the bandstructure in heterostructures of graphene over InSe and graphene over GaSe. An anticrossing is observed where the two bands cross in the 1st Brillouin zone of graphene, but the 2nd of InSe (GaSe). This anticrossing is replicated onto the 1st Brillouin zone of InSe (GaSe) by a ghost graphene-band umklapp-scattered by an InSe (GaSe) reciprocal lattice vector, in agreement with theoretical calculations. The resulting valence band alteration is twist-angle dependent and observed for various thicknesses of InSe and GaSe. This result demonstrates that it is possible to engineer strong interlayer coupling at defined energy and momenta in otherwise weakly coupled systems.

Johanna Zultak

University of Manchester