Absence of phonon-mediated superconductivity in La_3Ni_2O_7 under pressure

A recent experimental study announced the emergence of superconductivity in La_3Ni_2O_7 under pressure, with the highest observed superconducting transition temperature (T_c) reaching approximately 80 K beyond 14 GPa. While extensive studies have been devoted to the electronic correlations and potential superconducting pairing mechanisms, there lack investigations into the phonon properties and electron phonon coupling. Using density functional theory in conjunction with Wannier interpolation techniques, we study the phonon properties and electron phonon interactions in La_3Ni_2O_7 under 29.5 GPa. Our findings reveal that the electron phonon coupling is insufficient to solely explain the observed high superconducting T_c ∼ 80 K in La_3Ni_2O_7. And the calculated strong Fermi surface nesting may explain the experimental observed charge density wave transition in La_3Ni_2O_7. Our calculations substantiate La_3Ni_2O_7 is an unconventional superconductor.