Doping and Temperature Dependence of the Mass Enhancement Observed in the CuprateBi2Sr2CaCu2

Abstract

High-resolution photoemission is used to study the electronic structure of the cuprate superconductor, Bi(2)Sr(2)CaCu(2)O(8+delta), as a function of hole doping and temperature. A kink observed in the band dispersion in the nodal line in the superconducting state is associated with coupling to a resonant mode observed in neutron scattering. From the measured real part of the self-energy it is possible to extract a coupling constant which is largest in the underdoped regime, then decreasing continuously into the overdoped regime.

Determinant quantum Monte Carlo study of the two-dimensional single-band Hubbard-Holstein model

“…The proposed phonon update is then accepted with probability R = R ↑ R ↓ exp(−∆τ ∆E ph ) where ∆E ph is the total change in kinetic and potential energy associated with the update, and R σ is defined by Eq. (15). The ∆E ph term accounts for the contribution of H lat to the total action.…”

“…Perhaps the most discussed are the dispersion renormalizations in the nodal and anti-nodal regions of the Brillouin zone revealed by ARPES. [12][13][14][15][16][17][18][19] These manifest as sharp changes or "kinks" in the electronic band dispersion, which are generally believed to be due to coupling to a sharp bosonic mode. Although the identity of this mode (be it an electronic collective mode or one or more phonon modes) remains controversial, the appearance of the dispersion renormalizations at multiple energy scales ranging from 10 -110 meV strongly suggests coupling to a spectrum of oxygen phonons.…”

High-transition-temperature superconductivity in the absence of the magnetic-resonance mode

“…The ARPES data of ref. 6 for their T c = 55 K sample shows no resonance, so we can use this as an upper limit and our own 60 K sample as a lower limit, giving p = 0.225±0.010 for the value of the critical doping point.…”

“…3c we show the contribution of the resonance mode to the imaginary part of the self-energy as a function of doping, both directly and normalized as a percentage of the total scattering rate at 3000 cm −1 (see Methods). This is done to divide out the overall decrease of the coupling of the charge carriers to the bosonic fluctuations that occurs with increased doping [6,24].…”

Tunneling spectra of strongly coupled superconductors: Role of dimensionality

“…However, a comparison of the effective masses indicates that the couplings are not very different in Pb where 10 m ‫ء‬ / m = 2.1 and in the Bi-based cuprates where m ‫ء‬ / m varies between 1.5 and 3 as a function of doping. 11,12 Here we show that the large magnitude of the dip feature results from the low dimensionality of the materials and the associated singularities in the electronic DOS.…”