Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 40: Adsorption an Oberfl
ächen IV
O 40.9: Vortrag
Dienstag, 8. März 2005, 12:45–13:00, TU EB202
Alkali Intercalation in Transition metal dichalcogenides via Steps — •Claudia Ramirez1, Rainer Adelung2, Lutz Kipp 3, and Wolfgang Schattke1 — 1Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstrasse 15, 24098 Kiel, Germany — 2Technische Fakultät, Christian-Albrechts-Universität zu Kiel, Kaiserstrasse 2, 24143 Kiel, Germany — 3Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel,Leibnizstrasse 19, 24098 Kiel, Germany
The aim of this work was to understand how alkali metal atoms intercalate into transition metal dichalcogenides (TMDCs). To this end, a detailed investigation into the geometrical and electronic effects on TMDCs caused by adsorption and intercalation of alkali atoms was carried out by means of ab initio density-functional theory. The question of whether the alkali atoms can reach the van der Waals gap from the plain surface through the atomic planes was addressed. Because of the huge energy barrier involved in this process (3.81 eV), this type of intercalation can be excluded. The high value of the barrier suggests that the most probable path of intercalation must be through the edges or defects of the crystal such as steps or dislocations. The diffusion of Li adatom across and along two different steps, (1 0 1 0) and (1 2 1 1), was studied. STM experiments favor mainly the two step here considered. A model of alkali intercalation into TMDCs was obtained, namely via a (1 0 1 0) step.
This work was supported by the Deutsche Forschungsgemeinschaft (DFG), Forschergruppe FOR 353.