Comment on “Isotope effect in high-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:mrow></mml:math>superconductors”

Alexandrov, A. S.; Zhao, Guangyao

doi:10.1103/physrevb.80.136501

Cited by 8 publications

(7 citation statements)

References 37 publications

(43 reference statements)

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“…Substantial isotope effects on the carrier mass and a number of other independent observations (see e.g. [40] and references therein) unambiguously show that lattice vibrations play a significant although unconventional role in high-temperature superconduc-tors. Overall, it seems plausible that the true origin of high-temperature superconductivity should be found in a proper combination of strong electron-electron correlations with a significant EPI [41].…”

Section: Key Pairing Interaction and Unconventional Symmetry Of mentioning

confidence: 72%

High-temperature superconductivity: the explanation

Alexandrov

2011

Phys. Scr.

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Soon after the discovery of the first high temperature superconductor by Georg Bednorz and Alex Müller in 1986 the late Sir Nevill Mott answering his own question "Is there an explanation?" [Nature 327 (1987) 185] expressed a view that the Bose-Einstein condensation (BEC) of small bipolarons, predicted by us in 1981, could be the one. Several authors then contemplated BEC of real space tightly bound pairs, but with a purely electronic mechanism of pairing rather than with the electron-phonon interaction (EPI). However, a number of other researchers criticized the bipolaron (or any real-space pairing) scenario as incompatible with some angle-resolved photoemission spectra (ARPES), with experimentally determined effective masses of carriers and unconventional symmetry of the superconducting order parameter in cuprates. Since then the controversial issue of whether the electron-phonon interaction (EPI) is crucial for high-temperature superconductivity or weak and inessential has been one of the most challenging problems of contemporary condensed matter physics. Here I outline some developments in the bipolaron theory suggesting that the true origin of high-temperature superconductivity is found in a proper combination of strong electron-electron correlations with a significant finite-range (Fröhlich) EPI, and that the theory is fully compatible with the key experiments.

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Section: Key Pairing Interaction and Unconventional Symmetry Of mentioning

confidence: 72%

High-temperature superconductivity: the explanation

Alexandrov

2011

Phys. Scr.

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“…Also substantial isotope effects on the carrier mass and a number of other independent observations (see e.g. [6] and references therein) unambiguously show that lattice vibrations play a significant although unconventional role in high-temperature superconductors. Overall, it seems plausible that the true origin of high-temperature superconductivity could be found in a proper combination of strong electron-electron correlations with a significant EPI [7].…”

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confidence: 63%

Key Pairing Interaction in Layered Doped Ionic Insulators

Alexandrov

Bratkovsky²

2010

Phys. Rev. Lett.

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A controversial issue on whether the electron-phonon interaction (EPI) is crucial for high-temperature superconductivity or it is weak and inessential has remained one of the most challenging problems of contemporary condensed matter physics. We employ a continuum random phase approximation for the dielectric response function allowing for a self-consistent semianalytical evaluation of the EPI strength, electron-electron attractions, and the carrier mass renormalization in layered high-temperature superconductors. We show that the Fröhlich EPI with high-frequency optical phonons in doped ionic lattices is the key pairing interaction, which is beyond the BCS-Migdal-Eliashberg approximation in underdoped superconductors, and it remains a significant player in overdoped compounds.

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“…ψ / is the first derivative of ψ. Eqs. 1 and 2 are also valid for non-magnetic potential scattering for d-wave superconductors [25]. Therefore, irrespective of the nature of the pairbreaking impurity scatterer, the IE in cuprates can be expressed in terms of the experimentally measurable parameters T c and α p .…”

Section: Analysis Of the Ie Datamentioning

confidence: 98%

Isotope exponent in disordered underdoped and overdoped La214

Naqib

Islam

2012

J. Phys.: Conf. Ser.

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The effect of oxygen isotope substitution on T c has been analyzed for heavily underdoped and overdoped La 2-x Sr x Cu 1-y Zn y O 4 compounds with different Zn contents in the CuO 2 plane. The effect of Zn on the isotope exponent, α, was more pronounced in the case of the underdoped (x = 0.09) compounds compared to the overdoped (x = 0.22) ones. The variation of α with in-plane disorder can be described quite well within a model based solely on impurity induced Cooper pair-breaking in the case of the underdoped compounds. This model, on the other hand, fails to describe the behavior of α(y) for the overdoped samples, even though Zn still breaks pairs very effectively at this hole (Sr) content. We discuss the implications of these finding in details by considering the Zn induced magnetism, stripe correlations, and possible changes in the superconducting order parameter as number of charge carriers in the CuO 2 plane, p (≡ x), is varied.

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Comment on “Isotope effect in high-Tcsuperconductors”

Abstract: We show that the recent reinterpretation of oxygen-isotope effects in cuprate superconductors by Harshman et al. ͓Phys. Rev. B 77, 024523 ͑2008͔͒ is mathematically and physically incorrect violating the Anderson theorem and the Coulomb law.

Cited by 8 publications

References 37 publications

High-temperature superconductivity: the explanation

High-temperature superconductivity: the explanation

Key Pairing Interaction in Layered Doped Ionic Insulators

Isotope exponent in disordered underdoped and overdoped La214

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