Raman phonons of $α$-FeTe and Fe$_{1.03}$Se$_{0.3}$Te$_{0.7}$ single crystals

Xia, Tian-Long; Hou, D.; Zhao, S. C.; Zhang, A. M.; Chen, G. F.; Luo, J. L.; Wang, N. L.; Wei, J. H.; Lu, Z. -Y.; Zhang, Q. M.

Raman phonons of $α$-FeTe and Fe$_{1.03}$Se$_{0.3}$Te$_{0.7}$ single crystals

Authors

Description

The polarized Raman scattering spectra of nonsuperconducting $α$-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 $α$-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.
4 pages, 2 tables, 3 figures