Charge-transfer fluctuation,<i>d</i>-wave superconductivity, and the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">B</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi mathvariant="italic">g</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>Raman phonon in cuprates

Devereaux, T. P.; Virosztek, Attila; Zawadowski, A.

doi:10.1103/physrevb.51.505

Cited by 124 publications

(128 citation statements)

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“…[7] we consider only a reduced one band model appropriate for near half filling and take only the upper band into account. The electron -phonon reduced Hamiltonian for the B 1g q = 0 phonon was given as…”

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Enhanced electron–phonon coupling and its irrelevence to high T superconductivity

Devereaux

Virosztek

Zawadowski

et al. 1998

Solid State Communications

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It is argued that the origin of the buckling of the CuO2 planes in certain cuprates as well as the strong electron-phonon coupling of the B1g phonon is due to the electric field across the planes induced by atoms with different valence above and below. The magnitude of the electric field is deduced from new Raman results on YBa2Cu3O6+x and Bi2Sr2(Ca1−xYx)Cu2O8 with different O and Y doping, respectively. In the latter case it is shown that the symmetry breaking by replacing Ca partially by Y enhances the coupling by an order of magnitude, while the superconducting Tc drops to about two third of its original value.PACS numbers: 63.20.Kr, Recently there have been several suggestions [1] that out of plane oxygen vibrations of the CuO 2 plane may play an important role in mediating superconducting pairing in certain high temperature superconductors. It is also known that the presence of buckling (when the oxygen atoms are placed outside of the plane of the copper atoms) correlates with a strong interaction of a particular out-of-phase c-axis vibration (the so-called B 1g phonon) with planar quasiparticles [2]. As such, considerable attention has been focused on the strong interaction of electrons with this particular phonon and its connection to phonon-mediated d x 2 −y 2 superconductivity [3,4].The present paper provides the first direct experimental evidence to support that the buckling and consequent large value of the electron-phonon interaction are indeed correlated as a result of a local crystal electric field surrounding the vibrating atoms. Using the above ideas in conjunction with a three band model for the electron system, the strength of the electron phonon coupling and consequently the value of the electric field perpendicular to the plane can be determined by fitting the Fano interference in the B 1g Raman spectra. We find that even though the electron-phonon coupling can be engineered in different materials to increase by an order of magnitude, the effect has essentially no correlation with T c of the material. Therefore we argue that the B 1g phonon is irrelevant to superconductivity in the cuprates.Raman scattering data are presented in the normal state for different doping levels of YBa 2 Cu 3 O 6+x (Y-123) and Bi 2 Sr 2 CaCu 2 O 8 (Bi-2212). Experimentally the electron-phonon coupling can be determined from the line shape of the B 1g Raman phonon for both Y-123 where the surroundings of the CuO 2 plane is highly asymmetric and Bi-2212 where the plane is placed in a more symmetrical environment with respect to the charges of the nearby atoms.The resulting electron-phonon coupling is then used to interpret the Fano interference in the Raman spectra of Y-123, where the light is scattered by both the B 1g phonon and the electronic charge fluctuation in the plane described above.However, for Bi-2212 the B 1g phonon has an almost Lorentzian line shape indicating the lack of any substantial coupling between that phonon and the charge transfer between the two oxygens in accordance with the absence of a si...

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“…[7]. However, the electronic dispersion is now calculated for a three band model including direct O − O hopping t ′ as well as Cu − O hopping t [6].…”

mentioning

confidence: 99%

Enhanced electron–phonon coupling and its irrelevence to high T superconductivity

Devereaux

Virosztek

Zawadowski

et al. 1998

Solid State Communications

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“…Therefore, this is essentially different from the formula (32) in Ref. [5] derived by the Green functions method, and including the total phonon line width and, in addition, an intermixture of the intrinsic phonon line width.…”

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confidence: 89%

Fano Resonance in a Coupled Electron-Phonon System

Falkovsky

Klama

1997

Acta Phys. Pol. A

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Raman light scattering with excitation of electron-hole continuum and a phonon is investigated theoretically. The effect of a surface and screening of the electron-photon coupling and of the deformation potential as a result of the Coulomb interaction of the electrons is taken into account. The parameters of the 340 cm-1 resonance line in superconducting YBaCuO are estimated by comparing with experimental data.

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“…The full Fano line shape of the B 1g phonon was fit using the theory of Ref. 37, giving a sharp increase of λ ~ 0.1 at ~20 GPa [37]. The sharp change of λ is consistent with an increase of mobile charge carriers in the presence of an unscreened electron-phonon interaction [38].…”

Section: Insulator-metal Transition Bi2212: Coupling Anomalies Critmentioning

confidence: 99%

Magnon–phonon coupling and implications for charge-density wave states and superconductivity in cuprates

Struzhkin

Chen

2016

Low Temperature Physics

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The mechanism of high-temperature superconductivity of copper oxides (cuprates) remains unsolved puzzle in condensed matter physics. The cuprates represent extremely complicated system, showing fascinating variety of quantum phenomena and rich phase diagram as a function of doping. In the suggested "superconducting glue" mechanisms, phonon and spin excitations are invoked most frequently, and it appears that only spin excitations cover the energy scale required to justify very high transition temperature T c ~ 165 K (as in mercury-based triple layer cuprates compressed to 30 GPa). It appears that pressure is quite important variable helping to boost the T c record by almost 30 degrees. Pressure may be also considered as a clean tuning parameter, helping to understand the underlying balance of various energy scales and ordered states in cuprates. In this paper, a review of mostly our work on cuprates under pressure will be given, with the emphasis on the interactions between phonon and spin excitations. It appears that there is a strong coupling between superexchange interaction and stretching in-plane oxygen vibrations, which may give rise to a variety of complex phenomena, including the charge-density wave state intertwined with superconductivity and attracting a lot of interest recently. PACS

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Charge-transfer fluctuation,d-wave superconductivity, and theB1gRaman phonon in cuprates

Cited by 124 publications

References 23 publications

Enhanced electron–phonon coupling and its irrelevence to high T superconductivity

Enhanced electron–phonon coupling and its irrelevence to high T superconductivity

Fano Resonance in a Coupled Electron-Phonon System

Magnon–phonon coupling and implications for charge-density wave states and superconductivity in cuprates

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