Thermal-difference reflectance spectroscopy of the high-temperature cuprate superconductors

Holcomb, Matthew J.; Perry, Catherine L.; Collman, James P.; Little, W. A.

doi:10.1103/physrevb.53.6734

Cited by 90 publications

(53 citation statements)

References 73 publications

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“…What is so striking above, as with the original results from Stevens et al [96], is that they pin-point the same key resonant energy of 1.5 eV, identified originally by Holcomb et al [95] …”

Section: Brief Resumé Of the Chemical Negative-u Approach To Htscsupporting

confidence: 74%

“…In reference [1e] the work of Holcomb et al [95] and Stevens et al [96] Intersubsystem spin coupling of this form will account for peak C and for its rapid growth in intensity towards low T. As befits many-body processes the intensities of all three above features are observed to behave nonlinearly with applied laser power.…”

Section: Brief Resumé Of the Chemical Negative-u Approach To Htscmentioning

confidence: 99%

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Developments in the negative-Umodelling of the cuprate HTSC systems

Wilson

2001

J. Phys.: Condens. Matter

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This paper emphasizes once more the many strands which go into creating the unique and complex nature of the mixed-valent HTSC cuprates, above T c as below. Clearly it is not sensible to look in isolation to the lattice, magnetic or electronic aspects of the situation. Circumstances are too tightly coupled and interdependent. What one is in a position to do is to ascribe some preeminence in these matters. The line taken in this paper, as in its predecessors, is that charge constitutes the prime mover, but this taken within a chemical context, relating to bonding effects in the copper oxides and to a crucial shell-filling negative-U term of large magnitude. What dictates the uniqueness of copper in this is its particular position within the periodic table at the end of the 3dseries. This provides access to (i) three stable valencies, (ii) to the limited metallicity of tightbinding, mixed-valent YBa 2 Cu 3 O 7 , etc., (iii) to the p/d hybridized limitation of magnetic behaviour, and (iv) above all to the shell closure effects, with their dramatic energy adjustments of the relevant double-loading states when sited in high-valent local environment. This behaviour rests on the inhomogeneous electronic and structural conditions existing within these tight-binding mixed-valent systems. Normally such systems show strong positive-U behaviour and are magnetic. Here the shell-filling effects negate this U term to leave a net negative U eff of −3 eV per pair. That positions the bosonic electron pairs degenerate with E F . RVB spin coupling within the stripe phase geometry set up by the doped charge removes much spin-flip pair breaking, while the adopted 2D crystal structure with its saddle-point dominated F.S. provides the ideal k-space geometry from which to secure the negative-U driven pair formation. The Jahn-Teller effect associated with the d 9 electron count is crucial in upholding the two-subsystem nature of the HTSC materials.This paper looks at the support for this scenario that can be extracted from the recent work of Corson, Li, Mook, Valla, Norman, Varma, Gyorffy and many others. To the author it remains a mystery why other researchers have not examined the potential of this route for understanding the unique characteristics of the HTSC cuprates.3

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Section: Brief Resumé Of the Chemical Negative-u Approach To Htscsupporting

confidence: 74%

Section: Brief Resumé Of the Chemical Negative-u Approach To Htscmentioning

confidence: 99%

Developments in the negative-Umodelling of the cuprate HTSC systems

Wilson

2001

J. Phys.: Condens. Matter

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“…In addition to strong electron-phonon interactions, there is a pronounced coupling feature at an energy of about 2 eV in the optical reflectance data 74,75 . In Fig.…”

Section: Strong Coupling Between Electrons and Cu-o Charge-transfermentioning

confidence: 99%

Pairing interactions and pairing mechanism in high-temperature copper oxide superconductors

Zhao

2005

Phys. Rev. B

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The polaron binding energy Ep in undoped parent cuprates has been determined to be about 1.0 eV from the unconventional oxygen-isotope effect on the antiferromagnetic ordering temperature. The deduced value of Ep is in quantitative agreement with that estimated from independent optical data and that estimated theoretically from the measured dielectric constants. The substantial oxygenisotope effect on the in-plane supercarrier mass observed in optimally doped cuprates suggests that polarons are bound into the Cooper pairs. We also identify the phonon modes that are strongly coupled to conduction electrons from the angle-resolved photoemission spectroscopy, tunneling spectra, and optical data. We consistently show that there is a very strong electron-phonon coupling feature at a phonon energy of about 20 meV along the antinodal direction and that this coupling becomes weaker towards the diagonal direction. We further show that high-temperature superconductivity in cuprates is caused by strong electron-phonon coupling, polaronic effect, and significant coupling with 2 eV Cu-O charge transfer fluctuation.

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“…This value of ω c is of the order of the characteristic phonon energies. The statements about the sum rules violation, which has been made in the experimental papers [7][8][9][10] , mean that the value ω c in high-T c superconductors is much larger than in conventional ones. The maximum value ω c in high-T c systems, if they were also conventional, should be ≃ 0.1eV because they have a magnitude of the gap ∆ ≈ 20meV.…”

Section: It Leads Tomentioning

confidence: 99%

Electromagnetic response of superconductors and optical sum rule

Karakozov

Maksimov

Dolgov

2002

Solid State Communications

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The interrelation between the condensation energy and the optical sum rules has been investigated. It has been shown that the so called 'partial' sum rule violation is related mainly to a temperature dependence of the relaxation rate rather than to the appearance of superconductivity itself. Moreover, we demonstrate that the experimental data on the temperature dependence of the optical sum rule can be explained rather well by an account of strong electron-phonon interaction.Many recently published works are concerned with the origin of the condensation energy of the superconducting state, a possible violation of so-called 'optical sum rules', and the relation between these phenomena. These papers include both theoretical investigations [1][2][3][4][5][6] of these problems and experimental attempts 7-10 to observe a violation of the optical sum rule. Usually, the possibility of such violation is related to the change of the kinetic en-

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Thermal-difference reflectance spectroscopy of the high-temperature cuprate superconductors

Cited by 90 publications

References 73 publications

Developments in the negative-Umodelling of the cuprate HTSC systems

Developments in the negative-Umodelling of the cuprate HTSC systems

Pairing interactions and pairing mechanism in high-temperature copper oxide superconductors

Electromagnetic response of superconductors and optical sum rule

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