X-Ray spectra and electronic correlations of FeSe1-xTex
Journal
Physical Chemistry Chemical Physics
Journal Volume
13
Journal Issue
34
Pages
15666-15672
Date Issued
2011
Author(s)
Chen, C. L.
Dong, C. L.
Chen, J. L.
Guo, J.-H.
Yang, W. L.
Hsu, C. C.
Yeh, K. W.
Huang, T. W.
Mok, B. H.
Chan, T. S.
Lee, J. F.
Chang, C. L.
Rao, S. M.
Wu, M. K.
Abstract
Critical issues concerning emerging Fe-based superconductors include the degree of electron correlation and the origin of the superconductivity. X-Ray absorption spectra (XAS) and resonant inelastic X-ray scattering spectra (RIXS) of FeSe(1-x)Te(x) (x = 0-1) single crystals were obtained to study their electronic properties that relate to electron correlation and superconductivity. The linewidth of Fe L(2,3)-edges XAS of FeSe(1-x)Te(x) is narrower than that of Fe-pnictides, revealing the difference between their hybridization effects and localization character and those of other Fe-pnictides. While no significant differences exist between the Fe L-edge XAS and RIXS of FeSe(1-x)Te(x) and those of Fe-pnictides, Se K-edge and Te K-edge XAS exhibit substantial edge shift, suggesting that the superconductivity in an Fe-Se superconductor is strongly associated with the ligand states. A comparison of the Se K-edge and Te K-edge spectra reveals that the charge transfer may occur between Se and Te. Given the Coulomb interaction and the bandwidth, the spectral results indicate that FeSe(1-x)Te(x) is unlikely to be a weakly correlated system unlike the Fe-pnictides of the "1111" and "122" families. The spectral results further demonstrate that superconductivity in this class of Fe-based compounds is strongly associated with the ligand 4p hole state.
Type
journal article