A possible family of Ni-based high temperature superconductors

We suggest that a family of Ni-based compounds, which contain [Ni 2 M 2 O] 2− (M = chalcogen) layers with an antiperovskite structure constructed by mixed-anion Ni complexes, NiM 4 O 2 , can be potential high temperature superconductors (high- T c ) upon doping or applying pressure. The layer structures have been formed in many other transitional metal compounds such as La 2 B 2 Se 2 O 3 (B = Mn, Fe, Co). For the Ni-based compounds, we predict that the parental compounds host collinear antiferromagnetic states similar to those in iron-based high temperature superconductors. The electronic physics near Fermi energy is controlled by two e g d -orbitals with completely independent in-plane kinematics. We predict that the superconductivity in this family is characterized by strong competition between extended s -wave and d -wave pairing symmetries.