A new preprint appearing on ArXiv today adds another argument for the phonon mode (or modes) as being responsible for the kink in the band dispersion of high-Tc superconductors observed from ARPES measurement. The work studied the heavily-overdoped (Bi,Pb)2Sr2CuO6 and used a very high resolution, laser-based ARPES technique.
Abstract: Super-high resolution laser-based angle-resolved photoemission spectroscopy measurements have been carried out on a heavily overdoped (Bi,Pb)2Sr2CuO6 (Tc> 5 K) superconductor. Taking advantage of the high-precision data on the subtle change of the quasi-particle dispersion at different temperatures, we develop a general procedure to determine the bare band dispersion and extract the bosonic spectral function quantitatively. Our results show unambiguously that the 70 meV nodal kink is due to the electron coupling with the multiple phonon modes, with a large mass enhancement factor Lamda= 0.42 even in the heavily over-doped regime.
I've updated my original blog entry on this topic to reflect this new preprint.
Zz.
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