Phonon, two-magnon, and electronic Raman scattering of Fe1+yTe1-xSex

We have measured Raman-scattering spectra of single-crystalline FeTe0.6Se0.4 (T-c similar to 14.5 K) and its parent compound Fe1.074Te at various temperatures. In the parent compound Fe1.074Te, A(1g) and B-1g modes have been observed at 158 and 202 cm(-1), respectively, at 5 K. These frequencies agree qualitatively with the calculated results. Two-magnon excitation has been observed around 2300 cm(-1) for both compounds. A temperature dependence between the electronic Raman spectra below and above Tc has been observed, and 2 Delta and 2 Delta/k(B)T(C) have been estimated as 5.0 meV and 4.0, respectively.