ROLE OF HYBRIDIZATION IN THE SUPERCONDUCTING PROPERTIES OF AN EXTENDED d–p HUBBARD MODEL

Calegari, E. J.; Magalhães, S. G.; Gomes, A. A.

doi:10.1142/s0217979204023799

Cited by 8 publications

(30 citation statements)

References 6 publications

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“…Recently, the present authors have used the extended Hubbard model [13] with the Roth's method to study the role of hybridization in the superconductivity following closely the approach introduced by Beenen and Edwards [14]. As discussed in the references [8] and [15], the flattening of the bands is directly related to the band shift.…”

Section: Introductionmentioning

confidence: 99%

Superconductivity in a two dimensional extended Hubbard model

2005

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The Roth's two-pole approximation has been used by the present authors to investigate the role of d − p hybridization in the superconducting properties of an extended d−p Hubbard model. Superconductivity with singlet d x 2 −y 2 -wave pairing is treated by following Beenen and Edwards formalism. In this work, the Coulomb interaction, the temperature and the superconductivity have been considered in the calculation of some relevant correlation functions present in the Roth's band shift. The behavior of the order parameter associated with temperature, hybridization, Coulomb interaction and the Roth's band shift effects on superconductivity are studied. *

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Section: Introductionmentioning

confidence: 99%

Superconductivity in a two dimensional extended Hubbard model

2005

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“…[13,26,27,28], the band shift has been evaluated following the original Roth's procedure [12], where t d 0j = t d for the z nearest-neighbors has been considered. Consequently, this procedure removes the k-dependence of the correlation functions (mainly S j · S i ) present in the band shift.…”

Section: Model and General Formulationmentioning

confidence: 99%

“…In fact, the extended d−p Hubbard model has been previously studied within the n-pole approximation [26,27], in which d x 2 −y 2 -wave superconductivity has been treated following the approach proposed in Ref. [13].…”

Section: Introductionmentioning

confidence: 99%

SPECTRAL FUNCTION OF A d-p HUBBARD MODEL

Calegari

Magalhães

2011

Int. J. Mod. Phys. B

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This work investigates a d-p Hubbard model by the n-pole approximation in the hole-doped regime. In particular, the spectral function A(ω, k) is analyzed varying the filling, the local Coulomb interaction and the d − p hybridization. It should be remarked that the original n-pole approximation (Phys. Rev. 184 (1969) 451) has been improved in order to include adequately the k-dependence of the important correlation function Sj · Si present in the poles of the Green's functions. It has been verified that the topology of the Fermi surface (defined by A(ω = 0, k)) is deeply affected by the doping, the strength of the Coulomb interaction and also by the hybridization. Particularly, in the underdoped regime, the spectral function A(ω = 0, k) presents very low intensity close to the anti-nodal points (0, ±π) and (±π, 0). Such a behavior produces an anomalous Fermi surface (pockets) with pseudogaps in the region of the anti-nodal points. On the other hand, if the d − p hybridization is enhanced sufficiently, such pseudogaps vanish. It is precisely the correlation function Sj · Si present in the poles of the Green's functions which plays the important role in the underdoped situation. In fact, antiferromagnetic correlations coming from Sj · Si strongly modify the quasi-particle band structure. This is the ultimate source of anomalies in the Fermi surface in the present approach. IntroductionMore than two decades after the discovery of the cuprates [1], the theoretical description of this phenomenon still represents a challenge for the physicists. The fundamental aspects of the cuprates phase diagram can be described in the following terms. In the overdoped regime, there is a conventional normal metal, *

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“…In the previous work [3], we improved Ref. [5] to also include superconducting properties following closely the approach introduced by Beenen and Edwards [6].…”

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“…Nevertheless, in Ref. [3], the Roth's band shift has been estimated disregarding the temperature and the Coulomb interaction effects. In the present work, we have included these effects in the Roth's band shift.…”

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Role of hybridization in the superconducting properties of an extended d–p Hubbard model: a detailed numerical study

Calegari

Magalhães

Gomes

2005

Physica B: Condensed Matter

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The Roth's two-pole approximation has been used by the present authors to study the effects of the hybridization in the superconducting properties of a strongly correlated electron system. The model used is the extended Hubbard model which includes the d − p hybridization, the p-band and a narrow d-band. The present work is an extension of the previous Ref. [3]. Nevertheless, some important correlation functions necessary to estimate the Roth's band shift, are included together with the temperature T and the Coulomb interaction U to describe the superconductivity. The superconducting order parameter of a cuprate system, is obtained following Beenen and Edwards formalism. Here, we investigate in detail the change of the order parameter associated to temperature, Coulomb interaction and Roth's band shift effects on superconductivity. The phase diagram with Tc versus the total occupation numbers nT , shows the difference respect to the previous work.

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ROLE OF HYBRIDIZATION IN THE SUPERCONDUCTING PROPERTIES OF AN EXTENDED d–p HUBBARD MODEL

Cited by 8 publications

References 6 publications

Superconductivity in a two dimensional extended Hubbard model

Superconductivity in a two dimensional extended Hubbard model

SPECTRAL FUNCTION OF A d-p HUBBARD MODEL

Role of hybridization in the superconducting properties of an extended d–p Hubbard model: a detailed numerical study

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