2024/12/24 by Zhan Wang, Wang, Zhan, Zhang, Heng-Jia +4 · 3 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2412.18469
openalex publication_date 2024/12/24 · openalex created_date 2025/08/22 · openalex updated_date 2026/08/03
The bilayer structure of recently discovered high-temperature superconducting nickelates La3Ni2O7 provides a new platform for investigating correlation and superconductivity. Starting from a bilayer Hubbard model, we show that there is a molecular Mott insulator limit formed by the bonding band owing to Hubbard interaction U and large interlayer coupling. This molecular Mott insulator becomes self-doped due to electrons transferred to the antibonding bands at a weaker interlayer coupling strength. The self-doped molecular Mott insulator is similar to the doped Mott insulator studied in cuprates. We propose La3Ni2O7 to be a self-doped molecular Mott insulator, whose molecular Mott limit is formed by two nearly degenerate antisymmetric dx2-y2 and dz2 orbitals. Partial occupation of higher energy symmetric dx2-y2 orbital leads to self-doping, which may be responsible for high-temperature superconductivity in La3Ni2O7. The effects of Hund's coupling JH on the low-energy spectra are also studied via exact diagonalization. The proposed low-energy theory for La3Ni2O7 is found to be valid in a wide range of U and JH.