Evolution of the band structure of quasiparticles with doping in copper oxides on the basis of a generalized tight-binding method

Thet–Jmodel on a semi-infinite lattice

“…The latter ratio of parameters corresponds to hole-doped cuprates. 18,19 Equations (14) and (15) were solved by iterations for l xm = 4, using as the starting function for G(k y ωl x l ′ x ) Green's function of an unbounded crystal. To ensure the convergence of the iteration procedure an artificial broadening was introduced by substituting ω with ω + iη, η = 0.05t, in Eq.…”

Polaronic approach to strongly correlated electron systems with strong electron-phonon interaction

“…The detailed description of this procedure for the Hamiltonian of the p − d model can be found elsewhere. 15,29 The new oxygen hole operators are a linear combination of the Fourier transforms of the original p (x)qσ and p (y)qσ orbitals:…”

“…The explicit form of hopping terms depends on the chosen phase condition 23 and is consistent with the paper. 15 The largest energy scale in the problem is defined by the set of the Coulomb repulsion parameters which consists of intra-atomic interactions U d and U p and the nearest-neighbor copper-oxygen Coulomb parameter V pd .…”

“…In the original Hubbard model with 4 local states it is the 4 × 4 matrix. In the 5-band p − d model 15 with number of local electronic states N e ≈ 100 the |p q| matrix size is N e × N e . In polaronic approach 6,13 with number of coupled phonons N ph > 10 the size of |p p| matrix may be 1000 × 1000.…”

“…The generalized tight-binding method 15 and its ab-initio version LDA+GTB 16 have been developed previously to study the electronic structure of the cuprates, cobaltites and manganites within the multiband Hubbard model. The polaronic version of the GTB method (p-GTB) as well as the initial GTB is an example of cluster perturbation theory.…”