Boundary States in Graphene Heterojunctions
  A new type of states in graphene-based planar heterojunctions has been studied in the envelope wave function approximation. The condition for the formation of these states is the intersection between the dispersion curves of graphene and its gap modification. This type of states can also occur in smooth graphene-based heterojunctions. 
P. V. Ratnikov and A. P. Silin (Lebedev Physical Institute, Russian   Academy of Sciences)
cond-mat.mes-hall cond-mat.other