One-band tight-binding model parametrization of the high-Tccuprates including the effect ofkzdispersion

Abstract

We discuss the effects of interlayer hopping and the resulting kz-dispersion in the cuprates within the framework of the one-band tight binding (TB) model Hamiltonian. Specific forms of the dispersion relations in terms of the in-plane hopping parameters t, t ′ , t ′′ and t ′′′ and the effective interlayer hopping tz in La2−xSrxCuO4 (LSCO) and Nd2−xCexCuO4 (NCCO) and the added intracell hopping t bi between the CuO2 bilayers in Bi2Sr2CaCu2O8 (Bi2212) are presented. The values of the 'bare' parameters are obtained via fits with the first principles LDA-based band structures in LSCO, NCCO and Bi2212. The corresponding 'dressed' parameter sets which account for correlation effects beyond the LDA are derived by fitting experimental FS maps and dispersions near the Fermi energy in optimally doped and overdoped systems. The interlayer couplings tz and t bi are found generally to be a substantial fraction of the in-plane hopping t, although the value of tz in NCCO is anomalously small, reflecting absence of apical O atoms in the crystal structure. Our results provide some insight into the issues of the determination of doping from experimental FS maps in Bi2212, the role of intercell coupling in c-axis transport, and the possible correlations between the doping dependencies of the binding energies of the Van Hove singularities (VHSs) and various prominent features observed in the angle-resolved photoemission (ARPES) and tunneling spectra of the cuprates.

Enhancement of superconductivity via periodic modulation in a three-dimensional model of cuprates

“…Interestingly, the value of t z for which superconductivity reaches a minimum is of similar magnitude to the strength of c-axis hopping for various families of cuprates obtained as a fit to band structure 38 . Given this, if we imagine a system where t z is near or greater than the point of minimum superconducting T c in Figure 4, then enhancements of t z will generally lead to suppression of charge order and enhancement of superconductivity.…”

“…The exact expressions for each tunneling type are presented in Table II. Type A tunneling (nearest neighbor hopping along the c-axis) we introduce mainly for its simplicity, type B comes from a one-band tight binding fit to band structure calculations for LSCO 38 , and type C was proposed as an approximate tunneling form for several families of cuprate superconductor 39 . Despite the significant differences between these tunneling forms, it turns out that the effects we obtain are not specific to any of them, but are in all cases qualitatively similar.…”

d-Wave Superconductivity and s-Wave Charge Density Waves: Coexistence between Order Parameters of Different Origin and Symmetry

“…The quantities ∆ 0 , Σ 0 , and µ compose the full set of initial parameters for the problem in its s-version, i.e., for the CDW s-wave superconductor. The many-body correlation effects different from those described by the pairing terms (Equations (2) and (3)) in the Hamiltonian are incorporated into µ, since the very form of the FS calculated in microscopic and semi-microscopic models depends on the many-body electron-electron correlations [93,232,233].…”

Role of site selectivity, dimensionality, and strong correlations in angle-resolved photoemission from cuprate superconductors

“…Thus our analysis so far which implicitly assumes the presence of large FSs and LDA-type conventional electronic spectrum, even if with some renormalization, is generally limited to the description of the optimally doped and overdoped systems. Nevertheless, the LDA-based 'uncorrelated' bands often serve as the traditional starting point for addressing strong coupling effects via appropriately parametrized tight-binding model Hamiltonians [41]. This section discusses some results on LSCO and NCCO where LDA computations provide insight and/or parameters useful for understanding the behaviour of the correlated system.…”