Characteristics of Sr-doped LaNiO₂

Infinte-layer nickelates, RNiO₂ (R = La, Nd, Pr), have garnered continued interest since it was discovered they were superconducting [1] in the hopes of a better understanding of superconductivity in unconventional superconductors. Work [2] on the normal state of the undoped RNiO₂ (R = La, Nd), revealed a high temperature Curie-Weiss (CW) regime and a low tempterature Fermi Liquid (FL) regime. We perform charge self-consistent density function theory plus dynamical mean-field theory (DFT+DMFT) calculations on La_1-xSr_xNiO₂ to determine the effects of doping on the temperature phase boundaries for the the CW and FL regimes. We simulate the doping level using supercells for a range of dopings similar to that of experimental dopings (x=0.11-0.5). We find that in a certain range of doping the FL regime becomes diminished and the system exhibits fluctuating moment behavior down to low temperature for certain nickel sites. This may have consequences for superconductivity. Above this range of doping, the system approaches a state similar to the undoped compound.

[1] D. Li, K. Lee, Y. Wang, M. Osada, S. Crossley, H. R. Lee, Y. Cui, Y. Hikita, and H. Y. Hwang, Nature 572, 624 (2019)

[2] G. L. Pascut, L. Cosovanu, K. Haule, and K. F. Quader, Commun Phys 6, 45 (2023)