Volume 93, Number 4, February 2011
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||23 February 2011|
X-ray absorption spectroscopy investigation of the electronic structure of superconducting FeSex single crystals
Institute of Physics, Academia Sinica - Taipei 11529, Taiwan
2 National Synchrotron Radiation Research Center - Hsinchu 30076, Taiwan
3 Department of Physics, Tamkang University - Tamsui, Taipei County, Taiwan
4 Advanced Light Source, Lawrence Berkeley National Laboratory - Berkeley, CA 94720, USA
Accepted: 21 January 2011
X-ray absorption spectroscopy (XAS) Fe K-edge spectra of the FeSex (x = 1–0.8) single crystals cleaved in situ under vacuum reveal characteristic Fe 4sp states and a lattice distortion. The Se K-edge spectra point to a strong Fe 3d-Se 4p hybridization giving rise to itinerant charge carriers. A formal charge of ∼1.8+ for Fe and ∼2.2− for Se was evaluated from these spectra in the FeSex (x = 0.88). The charge balance between Fe and Se is assigned to itinerant electrons located in the Fe-Se hybridization bond. As x decreases the 4p hole count increases and a crystal structure distortion is observed that in turn causes the Fe separation in the ab-plane change from 4p orbital to varying (modulating) coordination. Powder X-ray diffraction (XRD) measurements also show a slight increase in lattice parameters as x decreases (increasing Se deficiency).
PACS: 78.70.Dm – X-ray absorption spectra / 74.70.Ad – Metals; alloys and binary compounds (including A15, MgB / 74.25.Jb – Electronic structure (photoemission, etc.)
© EPLA, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.