Orbital character variation of the Fermi surface and doping dependent changes of the dimensionality in BaFe_2-x Co_x As ₂ from angle-resolved photoemission spectroscopy

From a combination of high resolution angle-resolved photoemission spectroscopy and density functional calculations, we derive information on the dimensionality and the orbital character of the electronic states of BaFe _2-x Cox As2. Upon increasing Co doping, the electronic states in the vicinity of the Fermi level take on increasingly three-dimensional character. Both the orbital variation with kz and the more three-dimensional nature of the doped compounds have important consequences for the nesting conditions and thus possibly also for the appearance of antiferromagnetic and superconducting phases.