Ab initio calculation of electron-phonon linewidths and molecular dynamics with electronic friction at metal surfaces with numeric atom-centered orbitals

TL;DR

This paper introduces an improved all-electron numeric atomic orbital implementation for calculating electron-phonon interactions at metal surfaces, enhancing accuracy and convergence over previous plane-wave methods.

Contribution

The authors present a scalable, efficient all-electron code for electron-phonon linewidth calculations, demonstrating improved convergence and applicability to large surface models.

Findings

All-electron calculations show faster convergence than plane-wave methods.

Many literature electron-phonon linewidths may be underconverged.

New code enables analysis of vibrational linewidths in large surface models.

Abstract

Molecular motion at metallic surfaces is affected by nonadiabatic effects and electron-phonon coupling. The ensuing energy dissipation and dynamical steering effects are not captured by classical molecular dynamics simulations, but can be described with the molecular dynamics with electronic friction method and linear response calculations based on density functional theory. Herein, we present an implementation of electron-phonon response based on an all-electron numeric atomic orbital description in the electronic structure code FHI-aims. After providing details of the underlying approximations and numerical considerations, we present significant scalability and performance improvements of the new code compared to a previous implementation [Phys. Rev. B 94, 115432 (2016)]. We compare convergence behaviour and results of our simulations for exemplary systems such as CO on Cu(100), H$_2$ adsorption on Cu(111), and CO on Ru(0001) against existing plane wave implementations. We find that our all-electron calculations exhibit faster and more monotonic convergence behaviour than conventional plane-wave-based electron-phonon calculations. Our findings suggest that many electron-phonon linewidth calculations in literature may be underconverged. Finally, we showcase the capabilities of the new code by studying the contribution of interband and intraband excitations to vibrational linewidth broadening of aperiodic motion in previously unfeasibly large periodic surface models.