Relaxation of strongly coupled electron and phonon fields after photoemission and high-energy part of ARPES spectra of cuprates

TL;DR

This paper models the high-energy ARPES spectra of cuprates considering coupled electron-phonon relaxation, revealing spectral features consistent with experiments and highlighting the coexistence of localized and delocalized carriers.

Contribution

It introduces an analytical method to calculate high-energy ARPES spectra accounting for coupled electron-phonon relaxation in cuprates, explaining experimental spectral features.

Findings

Spectral features like broad Gaussian bands and vertical dispersion are accurately reproduced.

Coexistence of autolocalized and delocalized carriers is demonstrated in cuprates.

Large-radius autolocalized carriers may explain charge ordering phenomena.

Abstract

We consider photoemission from cuprate high-temperature superconductors taking into account joint relaxation of strongly coupled fields: a field of correlated electrons and phonon field. Such relaxation occurs in systems with predominantly long-range electron-phonon interaction at sufficiently high carrier concentration due to coexistence of autolocalized and delocalized carriers. A simple method to calculate analytically a high-energy part of the ARPES spectrum arising is proposed. The approach suggested yields all the high-energy spectral features like broad bands of Gaussian shape and vertical dispersion patterns being in good quantitative agreement with the experiments at any doping with both types of carriers. Demonstrated coexistence of autolocalized and delocalized carriers in cuprate superconductors is important for understanding their transport and magnetic properties. Presence of large-radius autolocalized carriers shown may be helpful in explanation of charge ordering in doped cuprates.