Kohn-Sham Exchange Potential for a Metallic Surface

HOROWITZ, CLAUDIO M.; PROETTO, CESAR; RIGAMONTI, SANTIAGO

PHYSICAL REVIEW LETTERS

The American Physical Society

Año: 2006 vol. 97 p. 268021 - 268024

0031-9007

The behavior of the surface barrier that forms at the metal-vacuum interface is important for several fields of surface science. Within the Density Functional Theory framework, this surface barrier has two non-trivial components: exchange and correlation. Exact results are provided for the exchange component, for a jellium metal-vacuum interface, in a slab geometry. The Kohn-Sham exact-exchange potential $V_{x}(z)$ has been generated by using the Optimized Effective Potential method, through an accurate numerical solution, imposing the correct boundary condition. It has been proved analytically, and confirmed numerically, that $V_{x}(z ightarrow infty ) ightarrow -,e^{2}/z$; this conclusion is not affected by the inclusion of correlation effects. Also, the exact-exchange potential develops a shoulder-like structure close to the interface, on the vacuum side. The issue of the classical image potential is discussed.