paper

Raman phonons of $I^\pm$ -FeTe and Fe $_{1.03}$ Se $_{0.3}$ Te $_{0.7}$ single crystals

arXiv:0811.2350 · doi:10.1103/PhysRevB.79.140510

Abstract

The polarized Raman scattering spectra of nonsuperconducting $I^\pm$ -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 $I^\pm$ -FeTe, the A $_{1 g}$ mode of the Te atom and the B $_{1 g}$ 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 $_{1 g}$ 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 $c m^{- 1}$ , which may be of electronic origin.

4 pages, 2 tables, 3 figures

Raman phonons of I^±-FeTe and Fe1.03​Se0.3​Te0.7​ single crystals

Abstract

Raman phonons of $I^\pm$ -FeTe and Fe $_{1.03}$ Se $_{0.3}$ Te $_{0.7}$ single crystals