Isotope effect in the pseudogap of high-temperature superconducting copper oxides

TL;DR

This study uses the Dynamical Cluster Approximation to analyze the isotope effect in the pseudogap of high-temperature cuprate superconductors, revealing a complex interplay between electronic interactions and phonons.

Contribution

It demonstrates that the pseudogap's isotope effect arises from electron-phonon interplay despite its non-phononic origin, with predictions for electron-doped materials.

Findings

Isotope effect observed in pseudogap consistent with experiments

Interplay between electronic repulsion and phonons affects antinodal spectra

Heavier quasiparticles appear along the nodal direction

Abstract

We study cuprates within Dynamical Cluster Approximation and find the pseudogap displays an isotope effect of the same sign as observed experimentally. Notwithstanding the non-phononic origin of the pseudogap the interplay between electronic repulsion and retarded phonon-mediated attraction gives rise to an isotope dependence of the antinodal spectra. Due to the strong momentum differentiation, such interplay is highly non-trivial and leads to the simultaneous presence of heavier quasiparticles along the nodal direction. We predict an isotope effect in electron-doped materials.