Presentation Information
[PC8-01-INV]Impact of electron-phonon coupling and Fermiology on Superconductivity in bilayer nickelates
*Xianxin Wu1 (1. Institute of Theoretical Physics, Chinese Academy of Sciences (China))
Keywords:
bilayer nickelates,pairing symmetry,functional renormalization group
The discovery of high-temperature superconductivity in bilayer nickelate La3Ni2O7 under pressure—and, more recently, in compressively strained thin films at ambient pressure—has sparked significant research interest. So far, its origin and underlying mechanism remain elusive. We investigate the microscopic origin of superconductivity in bilayer nickelates and report three results. (i) Conventional electron-phonon coupling (EPC) is insufficient to induce superconductivity; however, orbital-selective EPC from the unique out-of-plane breathing modes can cooperate with electronic correlations to enhance pairing and raise Tc. (ii) In compressively strained thin films, superconductivity can emerge when the dz2 bonding band approaches or crosses the Fermi level, which enhances the nesting between bonding and antibonding pockets, promote interlayer antiferromagnetic fluctuations and interlayer pairing. (iii) Nonlocal Coulomb interactions can reshape the correlated electronic states and affect superconductivity. Potential experimental implications and detection of pairing symmetries will also be discussed.