On edge states in superconductor with time inversion symmetry breaking

Superconducting states with different internal topology are discussed for the layered high-T_c materials. If the time inversion symmetry is broken, the superconductivity is determined not only by the symmetry of the superconducting state, but also by the topology of the ground state. The latter is determined the integer-valued momentum-space topological invariant N. The current carrying boundary between domains with different N (N_2 and N_1) is considered. The current is produced by fermion zero modes, which number per one layer is 2(N_2-N_1).