Electrons near graphene edge

To describe the behavior of a 2D electron near a graphene edge, one needs to know the boundary conditions for the effective (envelope) wave function, which obeys an equation of the Weyl-Dirac type. These conditions, which are deduced from general arguments, amount to a linear relation on the components of the spinor comprised of the envelope functions. In neglect of the intervalley interaction, the boundary conditions depend only on one real parameter, which contains a boundary of the general type. The spectrum of electronic edge states for the linear boundary is obtained