Electronic structure of the strongly hybridized ferromagnet CeFe2

We report on results from high-energy spectroscopic measurements on CeFe2, a system of particular interest due to its anomalous ferromagnetism with an unusually low Curie temperature and small magnetization compared to the ot her rare-earth iron Laves phase compounds. Our experimental results, obtain ed using core-level and valence-band photoemission, inverse photoemission a nd soft x-ray absorption techniques, indicate very strong hybridization of the Ce 4f states with the delocalized band states, mainly the Fe 3d states. In the interpretation and analysis of our measured spectra, we have made u se of two different theoretical approaches: The first one is based on the A nderson impurity model, with surface contributions explicitly taken into ac count The second method consists of band-structure calculations for bulk Ce Fe2. The analysis based on the Anderson impurity model gives calculated spe ctra in good agreement with the whole range of measured spectra, and reveal s that the Ce 4f-Fe 3d hybridization is considerably reduced at the surface , resulting in even stronger hybridization in the bulk than previously thou ght. The band-structure calculations are ab initio full-potential linear mu ffin-tin orbital calculations within the local-spin-density approximation o f the density functional. The Ce 4f electrons were treated as itinerant ban d electrons. Interestingly, the Ce 4f partial density of states obtained fr om the band-structure calculations also agree well with the experimental sp ectra concerning both the 4f peak position and the 4f bandwidth, if the sur face effects are properly taken into account. In addition, results, notably the partial spin magnetic moments, from the band-structure calculations ar e discussed in some detail and compared to experimental findings and earlie r calculations.