Efficient calculation of the mean inner potential of solids using density-functional theory

The mean inner potential of a solid is the average over a unit cell of the Coulomb potential due to its charges. This magnitude is of relevance, for example, in transmission electron microscopy imaging and holography. It has been computed in the past for a few materials with density-functional theory, typically using all-electron codes. In this work we present a recipe to do so using files produced by a standard projected-augmented wave code (VASP). We have use this method to asess the agreement with experiment regarding the values of the mean inner potential of alumina [1] and graphite [2] in the past. In this talk I will report how we recently exploited its flexibility to understand how trends in the value of the mean inner potential change, for example, depending on composition and surface orientation of elemental crystals.

[1] A. Auslender, M. Halabi, G. Levi, O. Diéguez, and A. Kohn; Ultramicroscopy 198, 18 (2019)

[2] A. Auslender, G. Levi, V. Ezersky, S. Gorfman, O. Diéguez, and A. Kohn, Carbon 179, 288 (2021)