Kink in cuprates: the role of the low-energy density of states

2023/12/08 by E. Razzoli, Razzoli, E., Fabio Boschini +31
Physics and Astronomy · #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)

paper · pdf · doi:10.48550/arxiv.2312.05378

openalex publication_date 2023/12/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The 40-70 meV band-structure renormalization (so-called kink) in high-temperature cuprate superconductors - which has been mainly interpreted in terms of electron-boson coupling - is observed to be strongly suppressed both above the superconducting transition temperature and under optical excitation. We employ equilibrium and time- and angle-resolved photoemission spectroscopy, in combination with Migdal-Eliashberg simulations, to investigate the suppression of the near-nodal kink in Bi₂Sr₂CaCu₂O_8+δ. We show that the ∼30% decrease of the kink strength across the superconducting-to-normal-state phase transition can be entirely accounted for by the filling of the superconducting gap, without additional consideration of temperature-dependent electron-boson coupling. Our findings demonstrate that consideration of changes in the density of states is essential to quantitatively account for the band structure renormalization effects in cuprates.

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