Nonplanar orbital effects on charge and spin fluctuations in doped cuprate superconductors

M. P. López Sancho; J. Rubio; M. C. Refolio; J. M. López Sancho

doi:10.1103/PhysRevB.49.9125

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Nonplanar orbital effects on charge and spin fluctuations in doped cuprate superconductors

M. P. López Sancho, J. Rubio, M. C. Refolio, J. M. López Sancho

DOI 10.1103/PhysRevB.49.9125 · Physical Review B

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Abstract

A general two-center six-band Hamiltonian, including copper dx2-y2 and d3z2-r2 as well as oxygen pσ and apical pz orbitals, is used to calculate the electronic structure of copper-oxide superconductors, within a mean-field approximation. Size effects as well as the role of apical oxygen have been investigated in clusters of different sizes as a function of doping. For square clusters (2n×2n) three low-energy self-consistent solutions have been found. The lowest-energy solution is of the charge- and spin-bag type, being characterized by enhanced Zhang-Rice correlations and a broad density-of-states structure in the Fermi-level (EF) region. Although this structure has mainly nonplanar character just at EF, its composition at the maximum, just below EF, is comparable with experimental results. These features may be relevant in the superconducting regime.