A review of electron–phonon coupling seen in the high‐<i>T</i><sub>c</sub> superconductors by angle‐resolved photoemission studies (ARPES)

In the study, we have calculated the dependence of the average value of the energy gap amplitude (G) on the hole concentration (p) and temperature (T ) for the Bi 2 Sr 2−x La x CuO 6+δ (BSLCO) superconductor. The ratio of the zero temperature energy gap to the critical temperature (R G ≡ G (0) /k B T C ) and the ratio of the energy gap to the pseudogap temperature (R G ≡ G (0) /k B T ) have been estimated on this basis. It has been found that the value of the parameter R G changes for p ∈ 0.127, 0.198 in the range from 32.98 to 7.98. On the other hand, R G takes the values from 2.60 to 3.28. The obtained results indicate that in the studied superconductor, the correlation exists only between the value of the energy gap and the pseudogap temperature, which stands in the sharp contrast with the predictions of the classical Bardeen-Cooper-Schrieffer (BCS) theory. In addition, the dependence of the energy gap on the momentum for the hole concentration corresponding to the maximum value of the pseudogap temperature and the maximum value of the critical temperature has been determined. It has been found that the theoretical results reproduce well the experimental data obtained by using the angle-resolved photoemission spectroscopy (ARPES) method.

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“…The values of the first two quantities are equal to: t = 350 meV [15][16][17] and ω 0 = 80 meV [18][19][20][21][22].…”

Section: The Model and The Resultsmentioning

confidence: 99%

Description of High-Temperature Superconducting State in BSLCO Compound

Szczȩśniak

Durajski

2014

J Supercond Nov Magn

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“…For describing the electronic subspace, optical and photoemission spectroscopies are well established 11,12,28 . Here we focus on the concept of ultrafast electron crystallography (UEC) to characterize hot phonons dynamics.…”

Section: II Methodsmentioning

confidence: 99%

Anisotropic electron-phonon coupling investigated by ultrafast electron crystallography: Three-temperature model

2013

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“…While longstudied from Raman, infrared, and neutron measurements, recent ARPES and scanning tunneling microscopy ͑STM͒ measurements on several cuprates has reinvigorated the exploration of the role of phonons on HTSC. 42 Experiments on Bi-2212, [43][44][45][46] 51 coupling to the neutron resonance and/or spin continuum, 52 and Engelsberg-Schrieffer renormalizations 53 due to coupling of electrons to a collection of optical phonons. These phonons include the out-of-phase c-axis oxygen buckling modes and the in-plane Cu-O bond-stretching modes.…”

Section: Introductionmentioning

confidence: 99%

Systematic study of electron-phonon coupling to oxygen modes across the cuprates

et al. 2010

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The large variations in T c across the cuprate families is one of the major unsolved puzzles in condensed matter physics and is poorly understood. Although there appears to be a great deal of universality in the cuprates, several orders of magnitude changes in T c can be achieved through changes in the chemical composition and structure of the unit cell. In this paper we formulate a systematic examination of the variations in electron-phonon coupling to oxygen phonons in the cuprates, incorporating a number of effects arising from several aspects of chemical composition and doping across cuprate families. It is argued that the electronphonon coupling is a very sensitive probe of the material-dependent variations in chemical structure, affecting the orbital character of the band crossing the Fermi level, the strength of local electric fields arising from structural-induced symmetry breaking, doping-dependent changes in the underlying band structure, and ionicity of the crystal governing the ability of the material to screen c-axis perturbations. Using electrostatic Ewald calculations and known experimental structural data, we establish a connection between the material's maximal T c at optimal doping and the strength of coupling to c-axis modes. We demonstrate that materials with the largest coupling to the out-of-phase bond-buckling ͑B 1g ͒ oxygen phonon branch also have the largest T c 's. In light of this observation we present model T c calculations using a two-well model where phonons work in conjunction with a dominant pairing interaction, presumably due to spin fluctuations, indicating how phonons can generate sizeable enhancements to T c despite the relatively small coupling strengths. Combined, these results can provide a natural framework for understanding the doping and material dependence of T c across the cuprates.

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A review of electron–phonon coupling seen in the high‐T_c superconductors by angle‐resolved photoemission studies (ARPES)

Cited by 163 publications

References 48 publications

Description of High-Temperature Superconducting State in BSLCO Compound

Description of High-Temperature Superconducting State in BSLCO Compound

Anisotropic electron-phonon coupling investigated by ultrafast electron crystallography: Three-temperature model

Systematic study of electron-phonon coupling to oxygen modes across the cuprates

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A review of electron–phonon coupling seen in the high‐Tc superconductors by angle‐resolved photoemission studies (ARPES)

Cited by 163 publications

References 48 publications

Description of High-Temperature Superconducting State in BSLCO Compound

Description of High-Temperature Superconducting State in BSLCO Compound

Anisotropic electron-phonon coupling investigated by ultrafast electron crystallography: Three-temperature model

Systematic study of electron-phonon coupling to oxygen modes across the cuprates

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A review of electron–phonon coupling seen in the high‐T_c superconductors by angle‐resolved photoemission studies (ARPES)