1. The nanoscale structure and unoccupied valence electronic states in FeSe1−xTex chalcogenides probed by X-ray absorption measurements
- Author
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Boby Joseph, Naurang L. Saini, Ekrem Yanmaz, M. Y. Hacisalihoglu, and Eugenio Paris
- Subjects
Valence (chemistry) ,Physical and Theoretical Chemistry ,Physics and Astronomy (all) ,Extended X-ray absorption fine structure ,Chemistry ,X-ray ,General Physics and Astronomy ,Molecular physics ,XANES ,Spectral line ,X-ray absorption fine structure ,Atomic physics ,Ternary operation ,Nanoscopic scale - Abstract
We have studied the nanoscale structure and unoccupied electronic states in FeSe1-xTex by a combined analysis of Se K, Te L1 and Fe K-edges X-ray absorption measurements. Extended X-ray absorption fine structure (EXAFS) results show that iron-chalcogen (Fe-Se and Fe-Te) distances in ternary FeSe1-xTex are similar to those measured for binary FeSe and FeTe. The local Fe-Se/Te distances determined by different absorption edges fit well in the characteristic Z-plot of random alloys, providing unambiguous support to the inhomogeneous nanoscale structure of the ternary FeSe1-xTex system. X-ray absorption near-edge structure (XANES) spectra reveal a gradual evolution of the unoccupied valence electronic states as a function of Te-substitution in FeSe1-xTex. The Fe 3d-Se 4p/Te 5p hybridization is found to decrease with Te-substitution, accompanied by an increase in unoccupied Se 4p states and a decrease in unoccupied Te 5p states. The results are discussed in the frame of local inhomogeneity in the FeSe1-xTex system driven by random alloying of Se/Te atoms.
- Published
- 2015
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