Regensburg 2019 – scientific programme
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O: Fachverband Oberflächenphysik
O 74: Focus Session: Growth, Properties and Application of Epitaxial Graphene (joint session DS/HL/O)
O 74.8: Talk
Thursday, April 4, 2019, 12:00–12:15, H32
Tuning the electronic properties of PbPb molecules by epitaxial graphene — •T.T.Nhung Nguyen1, U. Gerstmann2, T.N.Ha Nguyen1, and C. Tegenkamp1,3 — 1TU Chemnitz, Germany — 2Universität Paderborn, Germany — 3Leibniz Universität Hannover, Germany
Functionalization of graphene aimed for its application in nano-electronics is an important step. Among a variety of surface tailoring methods, molecular self-assembly gives rise to precisely control their interface by choosing appropriate molecules, e.g. non-planar lead-phthalocyanine (PbPc). By means of scanning tunneling microscopy and density functional theory (DFT) we studied in detail the adsorption of PbPc on graphene/SiC(0001). Thereby, we used as template both n-doped monolayer (MLG) and neutral quasi-free monolayer graphene (QFML). On both surfaces PbPc forms almost identical monolayer structures, in agreement with DFT. Upon adsorption of the molecules, where the central atom points away from the surface, the benzene rings undergo pronounced distortions, where adjacent rings rotate and bend in opposite directions giving rise to a chiral single domain structure. Despite the same adsorption geometry, the molecular states of PbPc on these two surfaces are strongly shifted with respect to each other. First DFT results show that the negatively charged MLG is responsible for this effect.