Absence of long wavelength nematic fluctuations in LiFeAs
  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. 
Adrian Merritt, Jose Rodriguez-Rivera, Yu Li, Weiyi Wang, Chenglin   Zhang, Pengcheng Dai, Dmitry Rezik
cond-mat.supr-con