Absence of long wavelength nematic fluctuations in LiFeAs

TL;DR

This study used inelastic neutron scattering to investigate nematic fluctuations in LiFeAs and found no evidence of such fluctuations, suggesting weak electron-phonon coupling or absence of nematic fluctuations.

Contribution

The paper provides direct experimental evidence showing the absence of long-wavelength nematic fluctuations in LiFeAs.

Findings

Phonons exhibit conventional behavior without signs of nematic fluctuations.

Nematic fluctuations are either weak or absent in LiFeAs.

Implications for understanding nematicity in Fe-based superconductors.

Abstract

We investigated long-wavelength nematic fluctuations in an Fe-based superconductor LiFeAs near q=(0.05,0,0) by measuring temperature-dependent renormalization of acoustic phonons through inelastic neutron scattering. We found that the phonons have conventional behavior, as would be expected in the absence of electronic nematic fluctuations. This observation implies that either electron-phonon coupling is too weak to see any effect or that nematic fluctuations are not present.