ARPES band maps of ferromagnetic iron: Theoretical simulation including e-e correlation

Many-body effects influence the energy-versus-momentum relation that is measured in angle resolvedphotoemission experiments and the quasiparticle band structure may be significantly differentfrom what is deduced within the independent particle model. Stimulated by recent high resolutionphotoemission data for iron showing quasiparticle renormalization close to the Fermi energy [1] wehave performed a systematic study 3d transition metals including on-site e-e correlation within the3Bs approach [2]; this amounts to solve a multi-orbital Hubbard Hamiltonian through an expansionof the interacting state in terms of configurations with one electron-hole pair added to the non interactingground state. The systematic analysis of metals of the 3d transition series allow us to showthat band occupation is a key parameter to quantify the effectiveness of many-body interactions. Wefind that e-e correlations are responsible for spin-dependent energy renormalization; in iron it turnsout that empty minority spin states are most affected while the same is true for filled majority spinones. A detailed analysis of energy dispersion curves after the inclusion of many body correctionand a comparison with measured spectra is also shown.