First-principle study of Sr-doping effect in Nd1-x SrxNiO2

Abstract

Sr-doped infinite layer nickelate Nd_1-xSr_xNiO₂ was recently reported as a superconductor analogous to the layered copper oxides. Previous works revealed that two bands of mainly Nd 5d and Ni 3d characters cross the Fermi level in NdNiO₂, whose behaviors under Sr doping are still unclear. We perform density functional theory calculations of supercell Nd_1-xSr_xNiO₂ to systematically study the evolution of its electronic structure at different doping levels. Our results show that a relative shift occurs between the Nd 5d and Ni 3d bands with Sr doping, deviating significantly from the commonly adopted rigid-band approximation for studying doped compounds. In addition, the O-p bands rise with respect to Fermi level when Sr concentration increases, resulting in a reduced charge transfer gap. We further estimate the hole concentrations on each band and Hall coefficients, and discuss their relevance to recent experiments.