Theory of isotope effect in photoemission spectra of high-T_c superconducting cuprates

TL;DR

This paper explores how isotope substitution affects the electronic spectral functions in high-T_c cuprates, proposing that changes in charge-order correlations, rather than just phonon frequencies, explain experimental observations.

Contribution

It introduces a model linking isotope effects to modifications in charge-order correlations, providing a new explanation for spectral shifts in superconducting cuprates.

Findings

Mass dependence of charge-order frequency alone is insufficient.

Isotope substitution alters charge-order correlations.

The model aligns well with experimental spectral data.

Abstract

We investigate the effect of isotope substitution on the electronic spectral functions within a model where the charge carriers are coupled to bosonic charge-order (CO) fluctuations centered around some mean frequency \omega_0 and with enhanced scattering at wave-vector q_c. It is shown that a mass dependence of \omega_0 is not sufficient in order to account, especially at high energies, for the dispersion shifts experimentally observed in an optimally doped superconducting cuprate. We argue that isotope substitution induces a change of the spatial CO correlations which gives good account of the experimental data.