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Liu, Rong; Veal, B. W.; Paulikas, A. P.; Downey, J.W.; Kostic, P.; Fleshler, S.; Welp, U.; Olson, C. G.; Wu, Xiaowei; Arko, A. J.; Joyce, J. J.

doi:10.1103/physrevb.46.11056

Cited by 135 publications

(56 citation statements)

References 50 publications

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“…One striking feature is the flattening at the top of the lower band around k = (π, π), extending to the saddlepoint at k = (π, 0) and halfway to k = (0, 0). Very flat bands have also been observed near the (π, 0) point in recent angular resolved photoemission (ARPES) experiments on hole doped cuprate superconductors such as 38,40 It is clear from our calculations that this feature is associated to a large extent with nearest neighbour antiferromagnetic correlations S i . S j < 0.…”

supporting

confidence: 54%

Superconductivity in the two-dimensional Hubbard model

1995

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Quasiparticle bands of the two-dimensional Hubbard model are calculated using the Roth two-pole approximation to the one particle Green's function. Excellent agreement is obtained with recent Monte Carlo calculations, including an anomalous volume of the Fermi surface near half-filling, which can possibly be explained in terms of a breakdown of Fermi liquid theory. The calculated bands are very flat around the (π, 0) points of the Brillouin zone in agreement with photoemission measurements of cuprate superconductors. With doping there is a shift in spectral weight from the upper band to the lower band. The Roth method is extended to deal with superconductivity within a four-pole approximation allowing electron-hole mixing. It is shown that triplet p-wave pairing never occurs. Singlet d x 2 −y 2 -wave pairing is strongly favoured and optimal doping occurs when the van Hove singularity, corresponding to the flat band part, lies at the Fermi level. Nearest neighbour antiferromagnetic correlations play an important role in flattening the bands near the Fermi level and in favouring superconductivity. However the mechanism for superconductivity is a local one, in contrast to spin fluctuation exchange models. For reasonable values of the hopping parameter the transition temperature T c is in the range 10-100K. The optimum doping δ c lies between 0.14 and 0.25, depending on the ratio U/t. The gap equation has a BCS-like form and 2∆

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supporting

confidence: 54%

Superconductivity in the two-dimensional Hubbard model

1995

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“…The shape of the Fermi surface is of interest because it constrains theoretical models. In Y Ba 2 Cu 3 O 7−x , excellent agreement has been obtained between angle-resolved photoemission experiments [1][2][3][4] and local density approximation (LDA) band structure calculations. [5][6][7] More recently, K.…”

Section: Introductionmentioning

confidence: 66%

“…The symmetry of electronic states comprising the Fermi surface is identified in Y Ba 2 Cu 3 O 7−x [3,4] because the material is underdoped for 6.35 < x < 6.95 and oxygen is removed predominantly from the chains. [10][11][12] The c−axis resistivity ρ c increases as x increases, and the interlayer coupling weakens.…”

Section: Introductionmentioning

confidence: 99%

Pb0.4Bi1.6
Ma
¹
,
Alméras
²
,
Kelley
³

et al. 1995
Phys. Rev. B

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“…This is due to the blocking of the chemical potential just below the Bosonic level. Another consequence of this fact is, as earlier mentioned, the weak dependence of the Fermi surface on the total number of carriers which seems to be actually observed [27]. The change in the number of carriers essentially results in the change of Me number of Bosons.…”

Section: A Generic Model For High-t Superconductivitymentioning

confidence: 50%

The Polaron Scenario for High-T_cSuperconductivity

Ranninger¹

1994

Acta Phys. Pol. A

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On the basis of experimental evidence we conclude that high-T c superconducting materials are composed of two distinct subsystems: one in which electrons are bound together in form of localized pairs of small polarons (bipolarons) and one in which electrons exist as strongly correlated Fermions. Upon doping one passes at a critical doping rate from the insulating parent compounds to metallic compounds. There, a charge transfer mechanism between the two subsystems sets in abruptly by which bipolarons can decay into pairs of electrons and vice versa. Such a picture can be modelled by a mixture of interacting Bosons and Fermions. A superconducting ground state for such a system develops at low temperature which is characterized by the opening of a gap in the single electron spectrum and the appearance of collective Boson excitations with a linear spectrum which is confined to the energy regime of the gap. Above TT , a pseudo-gap remains upon closing the superconducting gap. There are strong indications that the normal state has non Fermi liquid behaviour.

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Fermi-surface topology ofYBa2Cu3
Rong Liu
¹
,
B. W. Veal
²
,
A. P. Paulikas
³

et al.

Cited by 135 publications

References 50 publications

Superconductivity in the two-dimensional Hubbard model

Superconductivity in the two-dimensional Hubbard model

Pb0.4Bi1.6
Ma
¹
,
Alméras
²
,
Kelley
³

et al. 1995
Phys. Rev. B

The Polaron Scenario for High-T_cSuperconductivity

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Fermi-surface topology ofYBa2Cu3Rong Liu1, B. W. Veal2, A. P. Paulikas3 et al.

Cited by 135 publications

References 50 publications

Superconductivity in the two-dimensional Hubbard model

Superconductivity in the two-dimensional Hubbard model

Pb0.4Bi1.6Ma1, Alméras2, Kelley3 et al. 1995Phys. Rev. B

The Polaron Scenario for High-TcSuperconductivity

Contact Info

Product

Resources

About

Fermi-surface topology ofYBa2Cu3
Rong Liu
¹
,
B. W. Veal
²
,
A. P. Paulikas
³

et al.

Pb0.4Bi1.6
Ma
¹
,
Alméras
²
,
Kelley
³

et al. 1995
Phys. Rev. B

The Polaron Scenario for High-T_cSuperconductivity