Raman scattering study of NaFe${}_{0.53}$Cu${}_{0.47}$As

We use polarization-resolved Raman scattering to study lattice dynamics in NaFe${}_{0.53}$Cu${}_{0.47}$As single crystals. We identify 4 $A_{1g}$ phonon modes at 125, 172, 183 and 197 cm${}^{-1}$, and 4 $B_{3g}$ phonon modes at 101, 138, 173, 226 cm${}^{-1}$. The phonon spectra are consistent with the $Ibam$ group, which confirms that the Cu and Fe atoms form a stripe order. The temperature dependence of the phonon spectra suggests weak electron-phonon and magneto-elastic interactions.