Anisotropic atomic displacements, local orthorhombicity and anomalous local magnetic moment in Ba0.6K0.4Fe2As2 superconductor.

Autor: Tortora, L., Tomassucci, G., Pugliese, G. M., Hacisalihoglu, M. Y., Simonelli, L., Marini, C., Das, G., Ishida, S., Iyo, A., Eisaki, H., Mizokawa, T., Saini, N. L.
Zdroj: Physical Chemistry Chemical Physics (PCCP); 9/14/2024, Vol. 26 Issue 34, p22454-22462, 9p
Abstrakt: We have investigated the in-plane local structure of the Ba0.6K0.4Fe2As2 superconductor by polarized Fe K-edge extended X-ray absorption fine structure (EXAFS) measurements with temperature. The near neighbor bond distances and their stiffness, measured by polarized EXAFS in two orthogonal directions, are different suggesting in-plane anisotropy of the atomic displacements and local orthorhombicity in the title system. The X-ray absorption near edge structure (XANES) spectra reveal anisotropy of valence electronic structure that changes anomalously below ~100 K. The local iron magnetic moment, measured by Fe Kβ X-ray emission spectroscopy (XES), increases below the anomalous temperature and shows a decrease in the vicinity of the superconducting transition temperature (Tc ~ 36 K). The results provide a clear evidence of coupled local lattice, electronic and magnetic degrees of freedom to induce possible nematic fluctuations in an optimally hole doped iron-based superconductor. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index