Prediction of several Co-based La$_3$Ni$_2$O$_7$-like superconducting materials

Abstract: High temperature superconductivity has been found in Fe, Ni, and Cu compounds, but not Co, where the Ni compounds include the recently found bilayer nickelate La$_3$Ni$_2$O$_7$ under high pressure. Here we theoretically predict several Co-based La$_3$Ni$_2$O$_7$-like high-temperature superconducting materials. With electron doping to high-pressure bilayer cobaltate La$_3$Co$_2$O$_7$, we find that LaTh$_2$Co$_2$O$_7$, La$_3$Ni$_2$O$_5$Cl$_2$, and La$_3$Ni$_2$O$_5$Br$_2$ may show similar crystal structures and strongly correlated electronic structures to bilayer nickelate La$_3$Ni$_2$O$_7$ under high pressure. Within the random-phase approximation (RPA), the leading pairing symmetry in these materials is $s$-wave.