Orbital-selective superconductivity in the pressurized bilayer nickelate La3Ni2O7: An infinite projected entangled-pair state study

Abstract

The newly discovered high-๐‘‡๐‘ nickelate superconductor La3โขNi2โขO7 has generated significant research interest. To uncover the pairing mechanism, it is essential to investigate the intriguing interplay between the two ๐‘’๐‘”, i.e., ๐‘‘๐‘ฅ2โˆ’๐‘ฆ2 and ๐‘‘๐‘ง2 orbitals. Here we conduct an infinite projected entangled-pair state (iPEPS) study of the bilayer ๐‘กโˆ’๐ฝ model, directly in the thermodynamic limit and with orbitally selective parameters for ๐‘‘๐‘ฅ2โˆ’๐‘ฆ2 and ๐‘‘๐‘ง2 orbitals, respectively. The ๐‘‘๐‘ฅ2โˆ’๐‘ฆ2 electrons exhibit significant intralayer hopping ๐‘กโˆฅ (and spin couplings ๐ฝโˆฅ) as well as strong interlayer ๐ฝโŠฅ passed from the ๐‘‘๐‘ง2 electrons. However, the interlayer ๐‘กโŠฅ is negligible in this case. In contrast, the ๐‘‘๐‘ง2 orbital demonstrates strong interlayer ๐‘กโŠฅ and ๐ฝโŠฅ, while the inherent intralayer ๐‘กโˆฅ and ๐ฝโˆฅ are small. Based on the iPEPS results, we find clear orbital-selective behaviors in La3โขNi2โขO7. The ๐‘‘๐‘ฅ2โˆ’๐‘ฆ2 orbitals exhibit robust superconductive (SC) order driven by the interlayer coupling ๐ฝโŠฅ, while the ๐‘‘๐‘ง2 band shows relatively weak SC order as a result of small ๐‘กโˆฅ (lack of coherence) but large ๐‘กโŠฅ (strong Pauli blocking). Furthermore, by substituting rare-earth element Pm or Sm with La, we find an enhanced SC order, which opens up a promising avenue for discovering nickelate superconductors with even higher ๐‘‡๐‘

Publication
Phys. Rev. B