Fermiology of 122 family of Fe-based superconductors: An ab initio study

• DFT-based simulated Fermi surfaces of 122 family of Fe-based superconductors are studied.
• Room-temperature experimental structural parameters are used as input of our calculations.
• Topological changes in the FS structures for various kinds of doping are presented.
• Influence of dimensional cross-over of FS structures in magnetism and superconductivity is investigated.

Fermiology of various 122 systems are studied through first principles simulation. Electron doping causes expansion of electron and shrinkage of hole Fermi pockets. Isovalent Ru substitution (up to 35%) makes no visible modification in the electron- and hole-like Fermi surfaces (FSs) providing no clue regarding the nature of charge carrier doping. However, in case of 32% P doping there are considerable changes in the hole FSs. From our calculations, it is very clear that two-dimensionality of FSs may favour electron pair scattering between quasi-nested FSs which has important bearings in various orders (magnetic, orbital, superconducting) present in Fe-based superconductors.