  Fe-based superconductors have drawn much attention during the last decade due
to the finding of superconductivity in materials containing the magnetic
element, Fe, and the coexistence of superconductivity & magnetism. Extensive
study of the electronic structure of these systems suggested dominant role of d
states in their electronic properties, whereas the cuprate superconductors show
major role of the ligand derived states. In this article, we review some of our
results on the electronic structure of these fascinating systems employing high
resolution photoemission spectroscopy. The combined effect of electron
correlation and covalency reveal an interesting scenario in their electronic
structure. The ligand p states contribution at the Fermi level is found to be
much more significant than that indicated in earlier studies. Temperature
evolution of the energy bands reveals signature of transition akin to Lifshitz
transition in these systems.
