  In order to elucidate the role of surfaces at nonequilibrium phase
transitions we consider kinetic Ising models with surfaces subjected to a
periodic oscillating magnetic field. Whereas the corresponding bulk system
undergoes a continuous nonequilibrium phase transition characterized by the
exponents of the equilibrium Ising model, we find that the nonequilibrium
surface exponents do not coincide with those of the equilibrium critical
surface. In addition, in three space dimensions the surface phase diagram of
the nonequilibrium system differs markedly from that of the equilibrium system.
