Correlation-enhanced electron-phonon interaction in oxide superconductors from GW perturbation theory
ORAL · Invited
Abstract
Accurate and practical ab initio treatment of electron-phonon (e-ph) coupling is essential to the understanding of many condensed-matter phenomena. In this talk, I will present a recently developed ab initio linear-response method named GW perturbation theory (GWPT) that computes the e-ph interaction with the inclusion of the GW nonlocal, energy-dependent self-energy effects. GWPT goes beyond the commonly used density-functional perturbation theory (DFPT), which becomes inadequate in some materials when correlation effects are non-negligible. We demonstrate the GWPT method by showing that the e-ph coupling in Ba1-xKxBiO3 is significantly enhanced by many-electron correlation, strong enough to explain its high superconducting Tc of 32 K. Furthermore, GW-level anisotropic Eliashberg equation calculations suggest that infinite-layer nickelate superconductor Nd1-xSrxNiO2 may host a strong phonon-mediated s-wave two-gap superconductivity. I will also present studies on the e-ph coupling in cuprates and discuss new understanding in phenomena such as the ubiquitous 70-meV nodal dispersion kink.
*Works presented in this talk are supported by the US Department of Energy, US National Science Foundation, Center for Computational Study of Excited-State Phenomena in Energy Materials at the Lawrence Berkeley National Laboratory, and University of Southern California. We acknowledge computing resources provided by the National Energy Research Scientific Computing Center (NERSC) and Texas Advanced Computing Center (TACC).
–
Publication:[1] Z. Li, G. Antonius, M. Wu, F. da Jornada, and S. G. Louie, Phys. Rev. Lett. 122, 186402 (2019). [2] Z. Li, M. Wu, Y.-H. Chan, and S. G. Louie, Phys. Rev. Lett. 126, 146401 (2021). [3] Z. Li and S. G. Louie, arXiv:2210.12819 (2022).
