Electronic structures of electron- and hole-doped BaFe2As2 and nondoped SrFe2As2 have been studied systematically by x-ray emission spectroscopy at Fe and As K-absorption edges. The electron and hole doping causes slight increase of the integrated absolute difference (IAD) values of the Fe Kβ x-ray emission spectra which correlate to the local magnetic moment. Pressure decreases the IAD values and local magnetic moment, and induces the lower-spin states in these compounds. The pre-edge peak intensity of the XAS spectra at the Fe K-absorption edge increases with pressure in both compounds. This indicates an increase of the Fe 3d-As 4p hybridization. It was found that pressure induced a discontinuous increase of the prepeak intensity of the PFY-XAS spectra at the As K-absorption edge at low pressures in the BaFe2As2 systems. Our results may suggest that the Fe 3d-As 4p hybridization plays a key role in suppressing the AFM order by the doping or pressure and fluctuation of the local magnetic moment and the electron-electron correlation may also play a role on the physical properties of the iron superconductors.
ASJC Scopus subject areas
- Condensed Matter Physics