2026/07/20 by Guan-Hao Feng, Jun Quan
#cond-mat.supr-con #cond-mat.str-el
Recent experiments report high-temperature superconductivity in the hybrid nickelate La5Ni3O11, which is composed of alternating stacks of bilayer La3Ni2O7 and monolayer La2NiO4. However, the superconducting transition temperature Tc ≈ 64~K for La5Ni3O11 is remarkably lower than the 80~K observed for pressurized La3Ni2O7. Thus, an unified microscopic theory is required to address the difference in the pairing mechanisms between these systems. Here, we develop a phenomenological symmetry-based approach to systematically analyze the low-energy physics in La5Ni3O11, which is obtained by a charge self-consistent density functional theory plus dynamical mean-field theory method. We show that the superconductivity in La5Ni3O11 exhibits a two-gap nature, consisting of a leading interlayer pairing between the dz2 orbitals and a subleading intralayer pairing between the dx2-y2 orbitals. The reduction of Tc can be attributed to the diminished contribution of the interlayer pairing, as reflected by the hopping parameter ratio |t⊥z/t∥x|. Base on this unified picture, we discuss the possible pairing mechanism and the role of γ pocket for the superconductivity in the bilayer NiO2 planes of nickelate superconductors.