Raman phonons of $\alpha$-FeTe and Fe$_{1.03}$Se$_{0.3}$Te$_{0.7}$   single crystals
  The polarized Raman scattering spectra of nonsuperconducting $\alpha$-FeTe and of the newly discovered, As-free superconductor Fe$_{1.03}$Se$_{0.3}$Te$_{0.7}$ are measured at room temperature on single crystals. The phonon modes are assigned by combining symmetry analysis with first-principles calculations. In the parent compound $\alpha$-FeTe, the A$_{1g}$ mode of the Te atom and the B$_{1g}$ mode of the Fe atom are observed clearly, while in superconducting Fe$_{1.03}$Se$_{0.3}$Te$_{0.7}$, only a softened Fe B$_{1g}$ mode can be seen. No electron-phonon coupling feature can be distinguished in the spectra of the two samples. By contrast, the spectra of the superconducting system show a slight enhancement below 300$cm^{-1}$, which may be of electronic origin. 
Tian-Long Xia, D. Hou, S. C. Zhao, A. M. Zhang, G. F. Chen, J. L. Luo,   N. L. Wang, J. H. Wei, Z. -Y. Lu, and Q. M. Zhang