Effects of Sr doping on the electronic and spin-state properties of infinite-layer nickelates: Nature of holes

The recent discovery of high-T-c superconductivity in Sr-doped NdNiO2 has sparked a renewed interest in investigating nickelates as cuprate counterparts. Parent cuprates [Cu2+ : d(9)] are antiferromagnetic charge transfer insulators with the involvement of a single d(x2-y2) band around the Fermi level and strong p-d hybridization. In contrast, isoelectronic NdNiO2 [Ni+ : d(9)] is metallic with a d(x2-y2) band self-doped by Nd-d states. Using first principles calculations, we study the effect of Sr doping in the electronic and magnetic properties of infinite-layer nickelates as well as the nature of holes upon doping. We find that hole doping tends to make the material more cupratelike as it minimizes the self-doping effect, it enhances the p-d hybridization, and it produces low-spin (S = 0, nonmagnetic) Ni2+ dopants.