Kinks and waterfalls as signatures of competing order in angle-resolved photoemission spectra of La_{2-x}Sr_xCuO_4

TL;DR

This paper explains the origin of kinks and waterfalls in photoemission spectra of La_{2-x}Sr_xCuO_4 as resulting from coupling of quasiparticles with charge and spin collective modes near stripe instability, clarifying their nature.

Contribution

It demonstrates that both charge and spin collective modes are necessary to explain spectral features, resolving a long-standing debate about their origin in high-Tc cuprates.

Findings

Kinks and waterfalls are due to coupling with charge and spin modes.

Both phonon-like charge and spin modes are essential for accurate modeling.

Clarifies the bosonic mediators of electron interactions in La_{2-x}Sr_xCuO_4.

Abstract

We show that the so-called kinks and waterfalls observed in angle-resolved photoemission spectra of La2-xSrxCuO4, a prototypical high-Tc superconducting cuprate, result from the coupling of quasiparticles with two distinct nearly critical collective modes with finite characteristic wave vectors, typical of charge and spin fluctuations near a stripe instability. Both phonon-like charge and spin collective modes are needed to account for the kinked quasiparticle dispersions. This clarifies the long-standing question whether kinks are due to phonons or spin waves and the nature of the bosonic mediators of the electron-electron effective interaction in La2-xSrxCuO4.