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Nicholas Metropolis Award for Outstanding Doctoral Thesis Work in Computational Physics (2021): Correlation-enhanced electron-phonon interactions in oxide superconductors from linear-response GW perturbation theory

Invited

Abstract

A general, accurate and practical ab initio treatment of electron-phonon (e-ph) coupling is essential to the understanding of many excited-state phenomena. In this talk, I will present a new ab initio linear-response method named GW perturbation theory (GWPT) [1] that computes the e-ph interaction with the inclusion of the GW nonlocal, energy-dependent self-energy effects, going beyond the commonly used density-functional perturbation theory, which is inadequate in some materials. We apply GWPT to study e-ph interaction in oxide superconductors. We first show that the e-ph coupling in Ba1-xKxBiO3 is significantly enhanced by many-electron correlations, and is strong enough to explain its high superconducting Tc of 32 K as well as its doping dependence [1]. Secondly, with this method, we study a two-decade-old mystery – a ubiquitous 70-meV dispersion kink in cuprates observed in angle-resolved photoemission experiments, whereas the debate on its physical origin is yet to be settled. I will show, with ab initio GWPT results on the prototypical cuprate La2-xSrxCuO4, that the computed correlation-enhanced e-ph interaction gives rise to strong nodal kinks in quantitative agreement with experiments [2]. This study also provides new insights to the observed doping dependence of the photoemission kink in the cuprates.

[1] Z. Li, G. Antonius, M. Wu, F. H. da Jornada, and S. G. Louie, Phys. Rev. Lett. 122, 186402 (2019).
[2] Z. Li, M. Wu, Y.-H. Chan, and S. G. Louie, “Unmasking the origin of photoemission kinks in the Cuprates,” submitted.

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Presenters

  • Zhenglu Li

    Department of Physics, University of California, Berkeley, UC Berkeley & Lawrence Berkeley National Laboratory, University of California at Berkeley, and Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, University of California, Berkeley, Lawrence Berkeley National Laboratory and University of California at Berkeley, Department of physics, University of California at Berkeley, Berkeley, California

Authors

  • Zhenglu Li

    Department of Physics, University of California, Berkeley, UC Berkeley & Lawrence Berkeley National Laboratory, University of California at Berkeley, and Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, University of California, Berkeley, Lawrence Berkeley National Laboratory and University of California at Berkeley, Department of physics, University of California at Berkeley, Berkeley, California