BibTeX
@MISC{Sherman01and,
author = {A. Sherman and M. Schreiber},
title = {AND},
year = {2001}
}
Share
 |
 |
 |
 |
||
OpenURL
Abstract
Abstract. Hole and spin Green’s functions of the two-dimensional t-J model of the CuO2 planes are calculated in an approximation which retains the rotation symmetry in the paramagnetic state and has no presumed magnetic ordering. In this approximation Green’s functions are represented by continued fractions which are interrupted by decouplings with a vertex correction determined from the constraint of zero site magnetization in the paramagnetic state. Obtained results are shown to be in good agreement with Monte Carlo and exact diagonalization data. The calculated spectra demonstrate a pseudogap and a band splitting which are similar to those observed in Bi-based cuprate perovskites. For the description of strongly correlated electrons in CuO2 planes of perovskite high-Tc superconductors the two-dimensional t-J model is widely used (for a review see Ref. [1]). One of the most fruitful analytical methods for this model uses the spin-wave description of magnetic excitations. Some spectral peculiarities obtained in this approach are similar to those revealed from the photoemission, spin-lattice relaxation and neutron scattering experiments (see, e.g., Ref. [2]). However, this approximation has two serious shortcomings: (i) deviations from the Néel state are presumed2 to be small and (ii) the approximation violates the rotation symmetry of the paramagnetic state. In this paper we try to overcome these difficulties by using the description in terms of spin and hole operators and the continued fraction representations for Green’s functions. Self-energies are calculated by decouplings corrected with the use of the constraint of zero site magnetization in the paramagnetic state. The Hamiltonian of the t-J model reads H = ∑ nmσ tnma † nσamσ + 1
Keyphrases
paramagnetic state site magnetization two-dimensional t-j model rotation symmetry cuo2 plane bi-based cuprate perovskites monte carlo continued fraction good agreement serious shortcoming continued fraction representation calculated spectrum demonstrate t-j model approximation green function hole operator fruitful analytical method spin green function spin-wave description el state green function perovskite high-tc superconductors review see ref neutron scattering experiment vertex correction exact diagonalization data magnetic excitation magnetic ordering spectral peculiarity spin-lattice relaxation band splitting
