Self Energy and Fluctuation Spectra in Cuprates: Comparing Optical and Photoemission Results

TL;DR

This paper compares optical and photoemission methods to analyze self energies and fluctuation spectra in cuprates, revealing the universal presence of high energy bosonic fluctuations crucial for understanding high-temperature superconductivity.

Contribution

It demonstrates that high energy bosonic fluctuations are consistently observed across different spectroscopic techniques in cuprates.

Findings

High energy fluctuations span over 2 eV bandwidth.

Many studies focus only on the coherent band part.

Universal high energy bosonic fluctuations are confirmed.

Abstract

We compare efforts to extract self energies and fluctuation spectra of the cuprates using optical and photoemission techniques. The fluctuations have contributions from both the coherent and incoherent parts of the band, which are spread over the full bare bandwidth of >2eV. Many experimental studies concentrate on the coherent part of the band and hence miss higher energy fluctuations. Our study establishes the universal presence of high energy bosonic fluctuations across various spectroscopies as a key ingredient in the high temperature superconducting cuprates.