On triggering role of carrier mobility for Laughlin state organization

Recent experiments with suspended graphene have corroborated an important role of carrier mobility in the competition between Laughlin state and insulating state, presumably of Wigner-type electron crystal. Moreover, the fractional quantum Hall effect (FQHE) in graphene has been observed at low carrier densities when the interaction was reduced due to carrier dilution. This suggests that not solely interaction and the flat band with quenched kinetic energy may be important for formation of FQHE. Here, some exclusive for 2D topological arguments are supposed to explain the triggering role of carrier mobility in formation of the collective FQHE state, when conditions of sufficient flattening of a band and interaction presence are fulfilled.