Einladung zum Promotionsvortrag von Herrn Stefan Link:
„Intercalation of Graphene on SiC(0001): Ultra-high Doping Levels and New 2D materials“
The technique intercalation, as the insertion of foreign atom species between graphene and its substrate, was used to specifically modify graphene’s properties.
We show that the intercalation of Gd in epitaxial graphene on SiC(0001) introduces very strong n-type doping levels in the graphene. Our angle-resolved photoelectron spectroscopy
experiments reveal that the Van-Hove singularity, corresponding to the saddle points in graphene’s electronic spectrum, is reached at the Fermi level in monolayer graphene. Reaching
this regime is accompanied with strong renormalizations in graphene’s electronic spectrum. These are driven by strong electronic correlations and also by strong electron-phonon coupling.
In the case of bilayer graphene, the intercalation configuration introduces a strongly layerasymmetric charge carrier distribution. We show that under this condition, the two graphitic
layers effectively get decoupled. Theoretical models suggest, that this effect is driven by the strong interlayer asymmetry, which introduces a charge density redistribution within the layers.
Finally, we show that in the case of Au intercalation in epitaxial graphene on SiC(0001), the intercalant layer itself builds up a two dimensional band structure. This electronic system is in
first approximation independent on graphene related states. In this regard, the technique intercalation sets a new route for fabricating technologically appealing Van der Waals
heterostructures. (Vortrag auf Englisch)
Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.