A study of electronic structure of FeSe$_{1-x}$Te$_{x}$ chalcogenides by Fe and Se K-edge x-ray absorption near edge structure measurements

TL;DR

This study uses X-ray absorption near edge structure measurements at Fe and Se edges to analyze the electronic structure and orbital hybridization in FeSe$_{1-x}$Te$_{x}$ chalcogenides, revealing changes with Te substitution.

Contribution

It provides detailed insights into the hybridization of Fe 3d and chalcogen p states and their polarization dependence in FeSe$_{1-x}$Te$_{x}$ superconductors, advancing understanding of their electronic structure.

Findings

Fe K-edge pre-edge peak varies with Te substitution

Se K-edge white line peak resembles Se$^{2-}$ systems

Unoccupied Se orbitals near the Fermi level are mainly $p_{x,y}$ character

Abstract

Fe K-edge and Se K-edge x-ray absorption near edge structure (XANES) measurements are used to study FeSe$_{1-x}$Te$_{x}$ electronic structure of chalcogenides. An intense Fe K-edge pre-edge peak due to Fe 1s$\to$3d (and admixed Se/Te $p$ states) is observed, showing substantial change with the Te substitution and X-ray polarization. The main white line peak in the Se K-edge XANES due to Se 1s $\to$ 4p transition appear similar to the one expected for Se$^{2-}$ systems and changes with the Te substitution. Polarization dependence reveals that unoccupied Se orbitals near the Fermi level have predominant $p_{x,y}$ character. The results provide key information on the hybridization of Fe $3d$ and chalcogen $p$ states in the Fe-based chalcogenide superconductors.