Novel topological phase due to coexistence of superconductivity and spin-density wave: Application to high Tc superconductors

We consider a model of a coexistence phase between superconductivity(SC) and spin-density wave (SDW) where the SC is assumed to be of d(x2-y2) + id(xy) ((d)1 + id(2)) symmetry and the SOW order parameter is of s-wave as well as d(xy) symmetry. The Hamiltonian having such a symmetry is shown to yield a novel topological coexistence phase in addition to the conventional one It is shown that the amplitudes of both the order parameters determine a new phase diagram characterizing different topological phases. A possible experimental realization of such topological phases in a recent ARPES data of high T-c superconductors in the extreme undercloped regime is analyzed by considering the effective order parameter to be a combination of d(x2-y2) SC and d(xy) SDW. (C) 2014 Elsevier Ltd. All rights reserved.