Electronic Structure of FeAl Alloy Studied by Resonant Photoemission Spectroscopy and Ab Initio Calculations

摘要

Resonant photoemission spectroscopy has been used to investigate thecharacter of Fe 3d states in FeAl alloy. Fe 3d states have two differentcharacter, first is of itinerant nature located very close to the Fermi level,and second, is of less itinerant (relatively localized character), locatedbeyond 2 eV below the Fermi level. These distinct states are clearlydistinguishable in the resonant photoemission data. Comparison between theresults obtained from experiments and first principle based electronicstructure calculation show that the origin of the itinerant character of the Fe3d states is due to the ordered B2 structure, whereas the relatively lessitinerant (localized) Fe 3d states are from the disorders present in thesample. The exchange splitting of the Fe 3s core level peak confirms thepresence of local moment in this system. It is found that the itinerantelectrons arise due to the hybridization between Fe 3d and Al 3s-3p states.Presence of hybridization is observed as a shift in the Al 2p core-levelspectra as well as in the X-ray near edge absorption spectra towards lowerbinding energy. Our photoemission results are thus explained by theco-existence of ordered and disordered phases in the system.