Unlikelihood of a phonon mechanism for the high-temperature superconductivity in La3Ni2O7
Jing‐Yang You, Zien Zhu, Mauro Del Ben, Wei Chen, Zhenglu Li
Abstract
The discovery of ~80 K superconductivity in nickelate La 3 Ni 2 O 7 under pressure has ignited intense interest. Here, we present a comprehensive first-principles study of the electron-phonon ( e -ph) coupling in La 3 Ni 2 O 7 and its implications on the observed superconductivity. Our results conclude that the e -ph coupling is too weak (with a coupling constant λ ≲ 0.5) to account for the high T c , albeit interesting many-electron correlation effects exist. While Coulomb interactions (via G W self-energy and Hubbard U ) enhance the e -ph coupling strength, electron doping (oxygen vacancies) introduces no major changes. Additionally, different structural phases display varying characteristics near the Fermi level, but do not alter the conclusion. The e -ph coupling landscape of La 3 Ni 2 O 7 is intrinsically different from that of infinite-layer nickelates. These findings suggest that a phonon-mediated mechanism is unlikely to be responsible for the observed superconductivity in La 3 Ni 2 O 7 , pointing instead to an unconventional nature.