engleski

Magnetic and Ionic Effects in High-temperature Superconductors

Experimental magnetic responses of high-temperature superconductors are reviewed with particular regard to a minimal theoretical interpretation, compatible with the known data, which can account for the incommensurate response between T* and the superconducting Tc. Strong correlations dynamically redistribute the spectral weight of the effective low-energy fermions in the Brillouin zone so as to suppress incommensurabilities in the high-temperature particle-hole response of the doped metal in the relevant parameter space. Assuming additional order parameters below T* are of secondary importance, the magnetic pseudogap transition at T* is suggested to be a discommensuration of a high-energy dispersive mode of the copper spins in interaction with the predominantly oxygen nodal metal, with the appearance of a central peak. The physical origin of the effective interactions involved is described. Ionic (3D) effects on the metallic (2D) picture are qualitatively discussed.

high-temperature superconductors; magnetism; doping

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