Models of Strong Interaction in Flat-Band Graphene Nanoribbons: Magnetic   Quantum Crystals
  Graphene based nanostructures exhibit flat electronic energy bands in their single-particle spectrum. We consider interacting electrons in flat bands of zig-zag nanoribbons. We present a protocol for flat-band projection that yields interaction-only tight-binding models. We argue that, at low densities, flat bands can delocalize single-particle basis states to support ferromagnetic quantum crystal ground states. 
Hao Wang and V. W. Scarola
cond-mat.str-el