  We give a Hamiltonian discussion of surface states in an extra dimension as a
basis for chiral fermions in lattice models. Such modes appear with the Wilson
fermion action when the hopping parameter exceeds a critical value. The
association of such states with the closing and reopening of a band gap was
noted by Shockley in 1939. Poster presented by Michael Creutz at Lattice 93.
Uuencoded compressed postscript file.
