Lead Phonon Spectrum Calculated from Superconducting Density of States

Strong-coupling analysis of scanning tunneling spectra in Bi2Sr2Ca2CuBerthod1, Fasano2, Maggio-Aprile3 et al. 2013Phys. Rev. B

“…In classical superconductors, the phonon energies coincide with peaks in d 2 I/dV 2 . 8 We stress that in our spectra, the peak in d 2 I/dV 2 occurs at an energy ∼56 meV (triangles in Fig. 7), similar to the values observed in Bi-2212.…”

“…Such cases are the exception rather than the rule: These models will not capture, in particular, the "dip" feature ubiquitously present at energies above the superconducting gap. By analogy with phonon-related effects in classical superconductors, 7,8 the dip, also recently observed in pnictide superconductors, 9,10 is generally attributed to a collective mode. In order to analyze the phenomenon, an extension of the Eliashberg formalism to d-wave superconductors has been proposed.…”

Angle and frequency dependence of self-energy from spin fluctuation mediated d-wave pairing for high temperature superconductors

“…The most direct evidence of the spin fluctuation theory will be to detect the angle and frequency dependence of the diagonal and off-diagonal self-energy experimentally and compare it with the results presented here. This will be an extension of the McMillan-Rowell procedure of phonon superconductors [19] to d-wave pairing. The experiment of choice for this purpose will be the ARPES because of its high momentum and frequency resolution capability.…”

Tunneling spectra of strongly coupled superconductors: Role of dimensionality

“…The tunneling conductance, then, only depends on the gap function ⌬͑ ͒, whose energy variation reflects the singularities of the phonon spectrum. 14,15 The dimensionality of the materials does not enter in this formalism. The effect of a nonconstant N 0 ͑ ͒ on the gap function has been discussed in the context of the A15 compounds.…”