Sensitive dependence of pairing symmetry on Ni-eg crystal field splitting in the nickelate superconductor La3Ni2O7

The discovery of high-temperature superconductivity in La3Ni2O7 under pressure has drawn great attention. However, consensus has not been reached on its pairing symmetry in theory. By combining density-functional-theory (DFT), maximally-localized-Wannier-function, and linearized gap equation with random-phase-approximation, we find that the pairing symmetry of La3Ni2O7 is dxy, if its DFT band structure is accurately reproduced by a downfolded bilayer two-orbital model. More importantly, we reveal that the pairing symmetry of La3Ni2O7 sensitively depends on the crystal field splitting between two Ni-eg orbitals. A slight increase in Ni-eg crystal field splitting alters the pairing symmetry from dxy to s±. Such…

• YU
  York University
• NN
  National Natural Science Foundation of China

  Award: 12374064
• SA
  Science and Technology Commission of Shanghai Municipality

  Award: 23ZR1445400