Quasiparticle-like peaks, kinks, and electron-phonon coupling at the ($\pi$,0) regions in the CMR oxide La$_{2-2x}$Sr$_{1+2x}$Mn$_{2}$O$_{7}$

TL;DR

This study uses ARPES and INS to reveal quasiparticle peaks and electron-phonon interactions in La$_{2-2x}$Sr$_{1+2x}$Mn$_{2}$O$_{7}$, highlighting critical energy and momentum scales in the material's electronic structure.

Contribution

First observation of sharp quasiparticle-like peaks in a CMR manganite and identification of electron-phonon coupling with oxygen bond-stretching phonons at specific k-space regions.

Findings

Observation of quasiparticle-like peaks in CMR manganite

Identification of electron-phonon coupling with oxygen phonons

Matching energy and momentum of phonons to the kink features

Abstract

Using Angle-Resolved Photoemission (ARPES), we present the first observation of sharp quasiparticle-like peaks in a CMR manganite. We focus on the ($\pi$,0) regions of k-space and study their electronic scattering rates and dispersion kinks, uncovering the critical energy scales, momentum scales, and strengths of the interactions that renormalize the electrons. To identify these bosons we measured phonon dispersions in the energy range of the kink by inelastic neutron scattering (INS), finding a good match in both energy and momentum to the oxygen bond-stretching phonons.