Electron Correlation and the c-axis Dispersion of Cu d_z^2: a New Band Structure for High Temperature Superconductors

Abstract

Previously we showed the major effect of electron correlation in the cuprate superconductors is to lower the energy of the Cu d_x^2-y^2/O p_sigma (x^2-y^2) band with respect to the Cu d_z^2/O' p_z (z^2) band. In our 2D Hubbard model for La_1.85Sr_0.15CuO_4 (LaSCO), the z^2 band is narrow and crosses the standard x^2-y^2 band just below the Fermi level. In this work, we introduce c-axis dispersion to the model and find the z^2 band to have considerable anisotropic 3D character. An additional hole-like surface opens up in the z^2 band at (0,0,2pi/c) which expands with doping. At sufficient doping levels, a symmetry allowed x^2-y^2/z^2 band crossing along the (0,0)-(pi,pi) direction of the Brillouin zone appears at the Fermi level. At this point, Cooper pairs between the two bands (e.g. (k uparrow x^2-y^2/k downarrow z^2)) can form, providing the basis for the Interband Pairing Theory of superconductivity in these materials.

submitted to Phys. Rev. Lett. Related publications: Phys. Rev. B 58, 12303 (1998); Phys. Rev. B 58, 12323 (1998); cond-mat/9903088; cond-mat/9903105

References in corpus (1)

• Inter-Band Pairing Theory of Superconductivity

Cited by in corpus (7)

• The Antiferromagnetic Band Structure of La2CuO4 Revisited
• Doubling of the bands in overdoped Bi2Sr2CaCu2O8-probable evidence for c-axis bilayer coupling
• Inter-Band Pairing Theory of Superconductivity
• Ab Initio Evidence for the Formation of Impurity d(3z^2-r^2) Holes in Doped La_{2-x}Sr_xCuO_4
• Interplay between electron band-anticrossing and charge-density-wave instabilities
• The Importance of Static Correlation in the Band Structure of High Temperature Superconductors
• The NMR of High Temperature Superconductors without Anti-Ferromagnetic Spin Fluctuations