Abstract
Local structure of has been studied by extended x-ray absorption fine-structure (EXAFS) measurements as a function of temperature. Combination of Se and edge EXAFS has permitted to quantify the local interatomic distances and their mean-square relative displacements. The Fe-Se and Fe-Te bond lengths in the ternary system are found to be very different from the average crystallographic Fe-Se/Te distance, and almost identical to the Fe-Se and Fe-Te distances for the binary FeSe and FeTe systems, indicating distinct site occupation by the Se and Te atoms. The results provide a clear evidence of local inhomogeneities and coexisting electronic components in the , characterized by different local structural configurations, with direct implication on the fundamental electronic structure of these superconductors.
- Received 24 May 2010
DOI:https://doi.org/10.1103/PhysRevB.82.020502
©2010 American Physical Society