The $s^{\pm }$-Wave Superconductivity in the Pressurized La${}_4$Ni${}_3$O${}_{10}$

Abstract

Recently, evidence of superconductivity (SC) has been reported in pressurized La${}_4$Ni${}_3$O${}_{10}$. Here we study the possible pairing mechanism and pairing symmetry in this material. Through fitting the density-functional-theory band structure, we provide a six-orbital tight-binding model. In comparison with the band structure of La${}_3$Ni${}_2$O${}_7$, the additional non-bonding $d_{z^2}$ band is importance to the pairing mechanism here. When the multi-orbital Hubbard interactions are included, our random-phase-approximation based study yields an $s^{\pm }$-wave pairing. The dominant FS nesting with nesting vector ${\mathbf{Q}}_1\approx (\ddot{I}€,\ddot{I}€)$ is between the ${\hat{I}}^3$-pocket contributed by the bonding $d_{z^2}$ band top and the $\hat{I}{\pm }_1$-pocket contributed by the non-bonding $d_{z^2}$ band bottom, leading to the strongest pairing gap amplitude and opposite gap signs within the two regimes. The dominant real-space pairing is the interlayer pairing between the $d_{z^2}$ orbitals. We have also studied the doping dependence of the pairing symmetry and $T_c$.

5 pages, 5 figures