Origin of phonon anomalies in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Falter, Claus; Klenner, M.; Hoffmann, Georg; Chen, Qiang

doi:10.1103/physrevb.55.3308

Cited by 42 publications

(43 citation statements)

References 9 publications

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“…Consequently, this issue has been addressed in several theoretical papers. Falter and co-workers start from the electronic band structure calculated within the local density approximation (LDA) [10,11,12,13,14]. The failure of LDA theory to reproduce the insulating ground-state of the undoped parent compounds is remedied by suitably imposing the long-wavelength limit of the electronic polarizability [14].…”

Section: Discussionmentioning

confidence: 99%

Oxygen phonon branches in overdopedLa1.7Sr0.3Cu3O4

2006

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The dispersion of the Cu-O bond-stretching vibrations in overdoped La1.7Sr0.3CuO4 (not superconducting) has been studied by high resolution inelastic neutron scattering. It was found that the doping-induced renormalization of the so-called breathing and the half-breathing modes is larger than in optimally doped La1.85Sr0.15CuO4. On the other hand, the phonon linewidths are generally smaller in the overdoped sample. Features observed in optimally doped La1.85Sr0.15CuO4 which suggest a tendency towards charge stripe formation are absent in overdoped La1.7Sr0.3CuO4.

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Section: Discussionmentioning

confidence: 99%

Oxygen phonon branches in overdopedLa1.7Sr0.3Cu3O4

2006

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“…We point out, that some calculations which are based on the tight-binding parametrization of the band structure in Y Ba 2 [117]. Although this finding, that λ d is of the similar magnitude as λ s (λ d ≈ λ s ), is interesting and encouraging it seems that this method misses some ingredients of the ionic structure of the layered structure [52], [53].…”

Section: Lda Calculations Of λ In Htsc Oxidesmentioning

confidence: 90%

“…Since for some optical phonon modes one has ω ph > ω (c) p then nonadiabatic effects in the screening are important. The latter can give rise to much larger EPI coupling constant for this modes [52], [53].…”

Section: Electron-phonon Coupling In Raman Scatteringmentioning

confidence: 99%

“…its frequency dependence g α,n ∼ g 0 /ε cc (ω). This non-adiabaticity is partly accounted for in the Falter group [52], [53] by calculating the electronic dielectric function along the c-axis ε cc (k, ω) in the RPA approximation. The result is that g α,n is increased appreciable beyond its (well screened) metallic part, what gives a large increase of the EPI coupling not only in the phonon modes but also in the plasmon one.…”

Section: Lda Calculations Of λ In Htsc Oxidesmentioning

confidence: 99%

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Electron-Phonon Interaction and Strong Correlations in High-Temperature Superconductors: One can not avoid the unavoidable

Kulić¹

2004

AIP Conference Proceedings

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Abstract. The important role of the electron-phonon interaction (EPI) in explaining the properties of the normal state and pairing mechanism in high-T c superconductors (HTSC) is discussed. A number of experimental results are analyzed such as: dynamical conductivity, Raman scattering, neutron scattering, ARPES, tunnelling measurements, isotope effect and etc. They give convincing evidence that the EPI is strong and dominantly contributes to pairing in HTSC oxides. It is argued that strong electronic correlations in conjunction with the pronounced (in relatively weakly screened materials) EPI are unavoidable ingredients for the microscopic theory of pairing in HTSC oxides. I present the well defined and controllable theory of strong correlations and the EPI. It is shown that strong correlations give rise to the pronounced forward scattering peak in the EPI -the FSP theory. The FSP theory explains in a consistent way several (crucial) puzzles such as much smaller transport coupling constant than the pairing one (λ tr ≪ λ ), which are present if one interprets the results in HTSC oxides by the old Migdal-Eliashberg theory for the EPI. The ARPES shift puzzle where the nodal kink at 70 meV is unshifted in the superconducting state, while the anti-nodal one at 40 meV is shifted can be explained at present only by the FSP theory. A number of other interesting predictions of the FSP theory are also discussed.

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“…Common to both materials, however, is the strong component of ionic binding favoring long-ranged Coulomb interactions and a related strong nonlocal electron-phonon coupling in terms of localized charge fluctuations (CF's) of the ionic orbitals. This type of coupling has been shown in the cuprate-HTSC's to lead to the generic phonon anomalies of the high-frequency oxygen bond-stretching modes (OBSM) 1,2,3,4,5 . Recently, giant phonon anomalies for similar OBSM (oxygen breathing modes) also have been found by inelastic neutron scattering measurements in superconducting Ba 0.6 K 0.4 BiO 3 7,8,9 .…”

Section: Introductionmentioning

confidence: 99%

Microscopic modeling of phonon dynamics and charge response in metallicBaBiO3

2007

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We use our recently proposed microscopic modeling in the framework of linear response theory to investigate the complete phonon dispersion, the phonon density of states, certain phonon-induced electronic charge distributions and charge fluctuations (CF's) for anomalous soft modes of metallic BaBiO3 in its simple cubic phase where superconductivity with Tc up to 32 K appears. The theoretical approach already has been applied successfully to the cuprate high-temperature superconductors (HTSC's), simple ionic crystals (NaCl, MgO) and perovskite oxides (SrTiO3, BaTiO3). It is well suited for materials with a strong component of ionic binding and especially for "ionic" metals. In particular, the giant phonon anomalies related to the breathing vibration of the oxygen as found experimentally in superconducting doped Ba0.6K0.4BiO3, resembling those observed in the high Tc cuprates, are investigated. The origin of these anomalies is explored and attributed to a strong nonlocal coupling of the displaced oxygen ions to CF's of ionic type, essentially of the Bi6s-and Bi6p orbital. This points to the importance of both of these states at the Fermi energy. Starting from an ab-initio rigid ion model (RIM) we calculate the effect on the lattice dynamics and charge response of the most important electronic polarization processes in the material, i. e. CF's and dipole fluctuations (DF's). Taking into account these electronic degrees of freedom in linear response theory, we obtain a good agreement with the measured phonon dispersion and in particular with the strong phonon anomalies.

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Origin of phonon anomalies inLa2CuO4

Cited by 42 publications

References 9 publications

Oxygen phonon branches in overdopedLa1.7Sr0.3Cu3O4

Oxygen phonon branches in overdopedLa1.7Sr0.3Cu3O4

Electron-Phonon Interaction and Strong Correlations in High-Temperature Superconductors: One can not avoid the unavoidable

Microscopic modeling of phonon dynamics and charge response in metallicBaBiO3

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