title: Random alloy-like local structure of Fe(Se, S)(1-x)Te(x) superconductors revealed by extended x-ray absorption fine structure.
abstract: The local structure of Fe(Se, S)(1-x)Te(x) ternary (11-type) chalcogenides has been studied by temperature dependent Fe K-edge extended x-ray absorption fine structure measurements. We find that the Fe-Se and Fe-Te distances in ternary FeSe(1-x)Te(x) are closer to the respective distances in the binary systems, revealing significant divergence of the local structure from the average one. The mean square relative displacements show a systematic change with Te content, consistent with bond relaxation in the inhomogeneous ternary phases. Also, the Fe-Te and Fe-S distances in the FeS(0.2)Te(0.8) ternary system are found to be different in the crystallographically homogeneous structure. The observed features are characteristic of ternary random alloys, suggesting that a proper consideration should be given to the atomic distribution for describing the complex electronic structure of these multi-band Fe-based chalcogenides.
authors: Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy.
authors: A
authors: A
authors: Iadecola
authors: B
authors: B
authors: Joseph
authors: A
authors: A
authors: Puri
authors: L
authors: L
authors: Simonelli
authors: Y
authors: Y
authors: Mizuguchi
authors: D
authors: D
authors: Testemale
authors: O
authors: O
authors: Proux
authors: J-L
authors: JL
authors: Hazemann
authors: Y
authors: Y
authors: Takano
authors: N L
authors: NL
authors: Saini