Electronic structure and correlation of La${}_4$Co${}_2$NiO${}_8$Cl${}_2$: a theoretical proposal for a La${}_4$Ni${}_3$O${}_{10}$-like high-temperature superconductor

Based on the discovery of high-temperature superconductivity in the bilayer nickelate La${}_3$Ni${}_2$O${}_7$, several Co-based La${}_3$Ni${}_2$O${}_7$-like materials were theoretically predicted as possible high-temperature superconductors by electron doping. Motivated by these findings and the subsequent discovery of superconductivity in the trilayer nickelate La${}_4$Ni${}_3$O${}_{10}$ under high pressure, we propose and investigate a Co-based La${}_4$Ni${}_3$O${}_{10}$-like material. With electron doping to the high-pressure trilayer cobaltate La${}_4$Co${}_3$O${}_{10}$, using density functional theory combined with dynamical mean-field theory (DFT+DMFT), we find that the resulting compound La${}_4$Co${}_2$NiO${}_8$Cl${}_2$ exhibits a crystal structure and a strongly correlated electronic structure similar to those of La${}_4$Ni${}_3$O${}_{10}$ under high pressure. This suggests that this new compound may host high-temperature superconductivity.