𝑠±-wave superconductivity in pressurizedLa4⁢Ni3⁢O10

Abstract

Recently, evidence of superconductivity (SC) has been reported in pressurized La4⁢Ni3⁢O10. Here we study its possible pairing mechanism and pairing symmetry. Through fitting the density-functional-theory band structure, we provide a six-orbital tight-binding model. In comparison with the band structure of La3⁢Ni2⁢O7, the additional nonbonding 𝑑𝑧2 band is important to the pairing mechanism here. When the multiorbital Hubbard interactions are included, our random-phase-approximation based study yields an 𝑠±-wave SC. The dominant Fermi-surface nesting with vector 𝐐1≈(𝜋,𝜋) is between the 𝛾 pocket contributed by the bonding 𝑑𝑧2 band top and the 𝛼1 pocket contributed by the nonbonding 𝑑𝑧2 band bottom, leading to the strongest pairing amplitude and opposite gap signs within the two regimes. The dominant real-space pairing is the interlayer 𝑑𝑧2-orbital pairing. This 𝑠±-wave pairing pattern is insensitive to the band details. Upon electron doping, the 𝑇𝑐 would increase promptly before the system enters the Néel-ordered spin-density-wave phase.