Electrostatics of metallic surfaces in periodic density functional theory simulations within and beyond the linear response regime

Scivetti, Ivan; Gidopoulos, Nikitas I.; Teobaldi, Gilberto

Abstract

It has been more than fifty years already since the first ever Density Functional Theory (DFT) simulation of a jellium surface demonstrated that uniform electric fields and external point charges induce equivalent electrostatics in the limit of linear response. During the years that followed, improved jellium models and computational resources allowed including strong electric fields to explore the problem beyond linear response. Nowadays, most DFT simulations of metallic surfaces are routinely conducted using finite slabs with periodic boundary conditions (PBCs) and the pseudopotential method to account explicitly for the ionic lattice. Surprisingly, there is apparently no record of dedicated studies that jointly discuss how the electrostatic response of metallic slabs in strong electric fields is affected by the PBCs, the net charge, the number of atomic layers, the surface orientation and the adopted exchange-correlation potential. To investigate on these points, we carry out detailed DFT simulations for the low-index facets of Li, Al and Ag for neutral and charged slabs for varying ranges of external fields. Using key response parameters, we quantify and compare the electrostatics of slabs within and beyond the linear response regime, and find that neutral and charged slabs exhibit equivalent responses for equivalent external perturbations. To the best of our knowledge, this analysis also offers the first numerical demonstration that the electrostatic equivalence for the original jellium model also applies to slabs of finite size in PBCs. Our findings do not only invite the revision of some standard approximations to characterize the electrostatic response of metallic slabs, but also aim to support the development of semi-classical, DFT-based methods for metallic interfaces using PBCs.

Citation

Scivetti, I., Gidopoulos, N. I., & Teobaldi, G. (2023). Electrostatics of metallic surfaces in periodic density functional theory simulations within and beyond the linear response regime. Physical Review B, 108(16), Article 165423. https://doi.org/10.1103/PhysRevB.108.165423

• Journal Article Type: Article
• Acceptance Date: Oct 6, 2023
• Online Publication Date: Oct 26, 2023
• Publication Date: Oct 15, 2023
• Deposit Date: Oct 11, 2023
• Publicly Available Date: Oct 27, 2023
• Journal: Physical Review B
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 108
• Issue: 16
• Article Number: 165423
• DOI: https://doi.org/10.1103/PhysRevB.108.165423
• Public URL: https://durham-repository.worktribe.com/output/1789447