Implementation, validation and applications of electron-phonon calculations to large systems*

We generalize to extended systems a method recently developed [1] to carry out electron-phonon calculations, in which the dielectric matrix is represented in terms of dielectric eigenpotentials [2]. The latter are utilized for the evaluation of G₀W₀ quasi-particle energies, as well as dynamical and electron-phonon coupling matrices. The implementation is part of the WEST code [3] (www.west-code.org) and does not require summation over virtual electronic states or self-consistent density-functional-perturbation-theory calculations, thus making it scalable to large systems. Validation of the approach and applications to point defects in semiconductors are presented.

[1] Ryan L. McAvoy, Marco Govoni, and Giulia Galli. J. Chem. Theory. Comp. 14(12), 6269-6275, 2018.
[2] Hugh F. Wilson, François Gygi and Giulia Galli. Phys. Rev. B. 78, 113303 (2008); Hugh F. Wilson, Deyu Lu, François Gygi, and Giulia Galli. Phys. Rev. B. 79, 245106 (2009).
[3] Marco Govoni and Giulia Galli. J. Chem. Theory. Comput. 11, 2680 (2015)