Edge-on micro-Raman assessment of trigonal modes in partially ordered GaIn${\mathrm{P}}_2$

We present results of edge-on micro-Raman measurements performed on single variant [$1\overline{1}1$] spontaneously ordered GaIn${\mathrm{P}}_2$. Noticeable differences separate polarized backscattering spectra collected along the nonequivalent (110) and ($1\overline{1}0$) edge-on-like faces. In this way we have unambiguously identified the Raman modes at 208 and 354 ${\mathrm{cm}}^{-1\mathrm{}}$ as modes induced by the trigonal cationic arrangement with $A_1$ and LO symmetry, respectively. Furthermore, we were able to determine the relative magnitude of some components of the Raman tensors for these modes.