Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 102: New Methods: Theory

O 102.1: Vortrag

Donnerstag, 23. März 2017, 17:45–18:00, WIL C107

A generalized ’dipole correction’ for charged surfaces in the repeated slab approach — •Christoph Freysoldt, Arpit Mishra, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany

The charging of surfaces plays an important role in electrochemistry, electronic sensors, field evaporation in atom probe tomography, and many other situations. Ab initio calculations are hampered by the problem that appropriate electrostatic boundary conditions must be taken into account. We will demonstrate that the commonly used dipole correction for neutral asymmetric slabs, that takes care of differences in the work function on either side of the slab, can be generalized to charged surfaces. This allows for simulations of strong electric fields where linear-response-based extrapolation schemes may not be appropriate. We show how flat-band or band-bending conditions can be realized, and discuss how to meaningfully define a potential reference level for total energies. Last, we will highlight the importance of mechanical boundary conditions for charged slab calculations.