Toward a topological scenario for high-temperature superconductivity of copper oxides

The structure of the joint phase diagram demonstrating high-Tc superconductivity of copper oxides is studied on the basis of the theory of interaction-induced flat bands. Prerequisites for an associated topological rearrangement of the Landau state are established, and related non-Fermi-liquid (NFL) behavior of the normal states of cuprates is investigated. We focus on manifestations of this behavior in the electrical resistivity ρ(T), especially the observed gradual crossover from normal-state T-linear behavior ρ(T,x)=A1(x)T at doping x below the critical value xch of hole doping for termination of superconductivity, to T-quadratic behavior at x>xch, which is incompatible with predictions of the conventional quantum-critical-point scenario. It is demonstrated that the slope of the coefficient A1 is universal, being the same on both boundaries of the joint phase diagram of cuprates, in agreement with available experimental data.