Non-local dielectric screening in metals

TLDR

In metals, the electron potential is often modeled by dividing a bare ion pseudo‑potential by a dielectric constant, implicitly assuming the pseudo‑potential is local. The paper extends the theory to account for the non‑local nature of the pseudo‑potential. The authors perform numerical calculations using the Heine–Abarenkov model potential to implement the non‑local screening. The non‑local screening yields results that better match experiments than the local approximation, though the improvement is modest.

Abstract

Abstract The potential seen by an electron in a metal is frequently set up by starting with the pseudo-potential or model potential of the bare ion, and dividing by a dielectric constant to take account of the screening of the conduction electrons. Such a procedure assumes that the pseudo-potential is a ‘local’ potential. But in reality the pseudo-potential is a non-local operator, and the theory is extended in the present paper to take this correctly into account. Numerical calculations have been made with the model potential of Heine and Abarenkov (1964). The results are in somewhat better agreement with experiments than those of the local screening approximation, but the difference between them is not as large as might have been expected.