Phonon, Two-Magnon and Electronic Raman Scattering of Fe1+yTe1-xSex

TL;DR

This study investigates the Raman scattering spectra of FeTe0.6Se0.4 and Fe1.074Te, revealing phonon, two-magnon, and electronic excitations, and provides insights into their temperature-dependent electronic properties and superconducting gap.

Contribution

It presents detailed Raman spectra measurements of FeTe1-xSex compounds, including phonon modes, two-magnon excitations, and electronic spectra, with temperature dependence and superconducting gap estimation.

Findings

Phonon modes observed at 157.5 and 202.3 cm-1 in Fe1.074Te.

Two-magnon excitation around 2300 cm-1 in both compounds.

Superconducting gap estimated as 5.0 meV from electronic Raman spectra.

Abstract

We have measured Raman scattering spectra of single-crystalline FeTe0.6Se0.4 (T_c ~ 14.5 K) and its parent compound Fe1.074Te at various temperatures. In the parent compound Fe1.074Te, A1g and B1g modes have been observed at 157.5 and 202.3 cm-1, respectively, at 5 K. These frequencies qualitatively agree with the calculated results. Two-magnon excitation has been observed around 2300 cm-1 for both compounds. Temperature dependence between the electronic Raman spectra below and above T_c has been observed and 2\Delta and 2\Delta/k_BT_C have been estimated as 5.0 meV and 4.0, respectively.