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

•A model for a coexistence phase between superconductivity (SC) and spin-density wave (SDW) is considered.•The SC order parameter is taken as d+id symmetry and the SDW order parameter is taken as s  -wave as well as dxydxy symmetry.•A new phase diagram consisting of a topologically non-trivial and trivial coexistence phase is obtained.•The phase diagram is dictated by the amplitudes of both the order parameters.•A possible experimental realization of the topological coexistence phase in the recent ARPES data of high-TcTc cuprates is discussed.

We consider a model of a coexistence phase between superconductivity(SC) and spin-density wave(SDW) where the SC is assumed to be of dx2−y2+idxy(d1+id2)dx2−y2+idxy(d1+id2) symmetry and the SDW order parameter is of s  -wave as well as dxydxy 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 TcTc superconductors in the extreme underdoped regime is analyzed by considering the effective order parameter to be a combination of dx2−y2dx2−y2 SC and dxy SDW.