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Identifying valence structure in LiFeAs and NaFeAs with core-level spectroscopy.
E Z Kurmaev1, J A McLeod, N A Skorikov
1Institute of Metal Physics, Russian Academy of Sciences-Ural Division, 620219 Yekaterinburg, Russia.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|July 1, 2011
Summary
Iron-based superconductors like LiFeAs and NaFeAs exhibit electronic properties dominated by iron 3d states. These materials are confirmed as weakly or moderately correlated systems, distinct from strongly correlated oxides.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spectroscopy
Background:
- Understanding the electronic structure of iron-based superconductors is crucial for their technological application.
- The role of electron correlation in iron-based superconductors remains a subject of active research.
Purpose of the Study:
- To investigate the electronic structure of LiFeAs and NaFeAs using experimental and theoretical methods.
- To compare the electronic properties of these iron-based superconductors with other related iron compounds.
Main Methods:
- Resonant X-ray Emission Spectroscopy (XES) measurements at the Fe L(2,3) edges.
- First-principles electronic structure calculations.
Main Results:
- Fe 3d states significantly contribute to the density of states near the Fermi energy in LiFeAs and NaFeAs.
- Fe L(2,3) XES spectra show similar trends in energy and intensity ratios (I(L(2))/I(L(3))) across various FeAs compounds.
- The intensity ratio is closer to metallic iron than to strongly correlated iron oxide, indicating weaker correlation effects.
Conclusions:
- Iron-based superconductors are characterized as weakly or moderately correlated electronic systems.
- The findings provide insights into the fundamental electronic behavior governing superconductivity in these materials.
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