Evidence for polaronic supercarriers in the copper oxide superconductors La2–xSrxCuO4

Zhao, Guangyao; Hunt, M. B.; Keller, H.; Müller, K. A.

doi:10.1038/385236a0

Cited by 307 publications

(288 citation statements)

References 23 publications

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“…The most remarkable result is that the Meissner fraction of the 18 O sample is lower than that for the 16 O sample by about 23% in the case of x = 0.06. The isotope effects are reversible upon the isotope back-exchange [26,27], and reproducible in several sets of samples. For x = 0.06, we evaluate ∆m * * /m * * = 24(2)%.…”

Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

“…To gain more insight, it is essential to determine the oxygenisotope effect on the inplane effective supercarrier mass m * * ab . Although we have tentatively extracted the isotope dependence of m * * ab from experiments on powder samples [26], more reliable results should be obtained from experiments on single crystals.…”

Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

“…The small OIS observed in the optimally doped cuprates suggest that phonons might not be important in bringing about high temperature superconductivity. However, the doping dependence of the OIS has been extensively studied in different cuprate systems [17,[20][21][22][23][24][25][26][27]. For a particular family of doped cuprates the OIS increases with decreasing T c , and can be even larger than the BCS value.…”

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

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Unconventional isotope effects in the high-temperature cuprate superconductors

Zhao

Keller

Conder

2001

J. Phys.: Condens. Matter

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139

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We review various isotope effects in the high-Tc cuprate superconductors to assess the role of the electron-phonon interaction in the basic physics of these materials. Of particular interest are the unconventional isotope effects on the supercarrier mass, on the charge-stripe formation temperature, on the pseudogap formation temperature, on the EPR linewidth, on the spin-glass freezing temperature, and on the antiferromagnetic ordering temperature. The observed unconventional isotope effects strongly suggest that lattice vibrations play an important role in the microscopic pairing mechanism of high-temperature superconductivity.

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Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

Section: Large Oxygen-isotope Effect On the Effective Supercarriementioning

confidence: 99%

Section: Isotope Effect On the Superconducting Transition Temperamentioning

confidence: 99%

See 1 more Smart Citation

Unconventional isotope effects in the high-temperature cuprate superconductors

Zhao

Keller

Conder

2001

J. Phys.: Condens. Matter

Self Cite

139

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“…However, the recent measurement of large couplings between electrons and the lattice in the cuprate superconductors means that extensions to the conventional theories of superconductivity are required. [2][3][4] In particular, low dimensionality, intermediate dimensionless coupling constants of ϳ1, and large and active phonon frequencies of ϳ75 meV mean that BCS or the more advanced Migdal-Eliashberg ͑ME͒ theory cannot be applied. In fact, the large coupling constant and a propensity for strong renormalization in twodimensional ͑2D͒ systems, indicate that the bare unrenormalized phonon frequency could be several times greater than the measured 75 meV.…”

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confidence: 99%

d-wave superconductivity from electron-phonon interactions

Hague

2006

Phys. Rev. B

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I examine electron-phonon mediated superconductivity in the intermediate coupling and phonon frequency regime of the quasi-two-dimensional Holstein model. I use an extended Migdal-Eliashberg theory that includes vertex corrections and spatial fluctuations. I find a d-wave superconducting state that is unique close to half filling. The order parameter undergoes a transition to s-wave superconductivity on increasing filling. I explain how the inclusion of both vertex corrections and spatial fluctuations is essential for the prediction of a d-wave order parameter. I then discuss the effects of a large Coulomb pseudopotential on the superconductivity ͑such as is found in contemporary superconducting materials like the cuprates͒, which results in the destruction of the s-wave states, while leaving the d-wave states unmodified.

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“…In particular, anything that depends on the (bi)polaron mass should exhibit a large isotope exponent [86]. A large isotope effect was observed, for example, on the magnetic penetration depth in cuprates [97,98,99], which was interpreted as evidence for bipolaronic carriers in the superconducting state.…”

Section: Isotope Exponentsmentioning

confidence: 99%

Path Integrals in the Physics of Lattice Polarons

Kornilovitch

2007

Polarons in Advanced Materials

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Summary.A path-integral approach to lattice polarons is developed. The method is based on exact analytical elimination of phonons and subsequent Monte Carlo simulation of self-interacting fermions. The analytical basis of the method is presented with emphasis on visualization of polaron effects, which path integrals provide. Numerical results on the polaron energy, mass, spectrum and density of states are given for short-range and long-range electron-phonon interactions. It is shown that certain long-range interactions significantly reduce the polaron mass, and anisotropic interactions enhance polaron anisotropy. The isotope effect on the polaron mass and spectrum is discussed. A path-integral approach to the Jahn-Teller polaron is developed. Extensions of the method to lattice bipolarons and to more complex polaron models are outlined.

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Evidence for polaronic supercarriers in the copper oxide superconductors La2–xSrxCuO4

Cited by 307 publications

References 23 publications

Unconventional isotope effects in the high-temperature cuprate superconductors

Unconventional isotope effects in the high-temperature cuprate superconductors

d-wave superconductivity from electron-phonon interactions

Path Integrals in the Physics of Lattice Polarons

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