The electronic properties in the hole-doped 1111 compounds: An ab-initio description

•LSDA+U calculations were performed on the nonsuperconducting PrFeAsO and superconducting Pr1−xSrxFeAsO.•A detailed comparison between the two compounds has been established.•The band structures and Fermi surfaces of both systems have been studied and compared.•The interatomic distances and bond angles play an important role in the electronic structures of these itinerant AFM iron oxypnictides. First principles calculations are performed to study the electronic structure of the iron-based superconductor Pr1−xSrxFeAsO with 25% strontium concentration through a careful analysis of the Fermi surfaces and band dispersions in the vicinity of the Fermi level using the accurate augmented plane-wave plus local orbital method. We have applied the onsite Coulomb potential on the Pr-derived 4f orbitals for both PrFeAsO and Pr6Sr2Fe8As8O8 compounds. LSDA+U results show the main effects of the strontium states in the doped system. The volume, Fe-Pr distances and α (Fe-As-Fe) angle increase with the insertion of strontium atoms. The pocket with dxy character in the PrFeAsO becames into a pocket dz2 character in the Pr1−xSrxFeAsO compound when As approximates to the Fe-plane. Finally, the Sr-doping induces the changes in the interatomic distances and bond angles, which are responsible for the phenomenon of superconductivity in this family of compounds.