# Direct observation of self energy signatures of the resonant collective mode in Bi2Sr2CaCu2O8

## TL;DR

This study uses high-resolution ARPES to directly observe the self-energy signatures of a resonant collective mode in Bi2212, revealing its role in the characteristic spectral features of cuprate superconductors.

## Contribution

It provides direct experimental evidence linking the resonant mode to the spectral hump-dip-peak structure and its temperature-dependent behavior in cuprates.

## Key findings

- Resonant mode interaction peaks in the antinodal self energy.
- Interaction vanishes above Tc, localized near the antinode.
- Clarifies the electron-boson coupling mechanism in cuprates.

## Abstract

We use high resolution ARPES to study the resonant, collective excitation mode in the superconducting state of Bi2212. By collecting very high quality data we found new features in the self energy in the antinodal region, where the interaction of electrons with the mode is the strongest. This interaction leads to pronounced peak in the scattering rate and we demonstrate that this feature is directly responsible for well known hump-dip-peak structure in cuprates. By studying how the weight of this peak changes with temperature we unequivocally demonstrate that interaction of electrons with resonant mode in cuprates vanishes at Tc and is very much localized in the momentum space close to the antinode. These findings present a consistent picture of line shape and self energy signatures of the electron-boson coupling in cuprates and resolve long standing controversy surrounding this issue. The momentum dependence of the strength of electron-mode interaction enables development of quantitative theory of this phenomenon in cuprates.