First-principles study of the transition metal-doped iron-based superconductor AFe2As2 (A = Ba, Sr)

The characteristics of structural changes, Fe magnetic moment and electronic structure of TM (TM = Co, Ni, Rh, Pd, Ir and Pt)-doped AFe2As2 (A = Ba, Sr) were studied by first-principles calculations. After the introduction of the dopants, almost all the Fe–Fe distances become longer. The nesting between the electron pockets and the hole pockets is formed. The Fermi level has a tendency to move from the hole band to the electron band. With the decrease in Fe magnetic moment, the width of Fe 3d and As 4p hybridized bands is increased, which is considered to be the decrease in electronic localized character and the increase in itinerary. The observed common features in our calculations provide information on the generation of superconductivity in iron-based superconductors AFe2As2 (A = Ba, Sr).