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HL: Fachverband Halbleiterphysik

HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)

HL 39.16: Poster

Dienstag, 17. März 2015, 14:00–20:00, Poster F

Scanning Tunneling Microscopy And Spectroscopy of Metallic Islands on Graphene/Cu and Graphene/SiO₂ — •Anne Holtsch, Tobias Euwens, and Uwe Hartmann — Institut für Experimentalphysik, Universität des Saarlandes, Saarbrücken

Using scanning probe techniques we investigate how graphene interacts electronically with various types of substrates in the presence of metallic islands. In the case of transition metals, due to the hybridization of their d orbital the p_z orbital of graphene, the band structure is significantly altered with respect to graphene [1]. By contrast, the interaction is expected to be much weaker for insulating SiO₂. Using scanning tunneling spectroscopy (STS) the different effects of the two substrates Cu and SiO₂ are investigated for absent and present metallic islands. The islands made from gold, nickel, or cobalt are put onto graphene by in-situ evaporation. Afterwards their relative orientation with respect to the graphene lattice was observed by scanning tunneling microscopy (STM). We further heat the system to induce intercalation of the metallic islands, resulting in a second change of the band structure of the sample. Due to specific Moiré patterns the intercalation processes are observable in STM images. Our goal is to evaluate how strongly the band structure measured via STS depends on the material properties of both the substrate and the metallic islands.

[1] E. N. Voloshina and Yu. S. Dedkov, Mater. Res. Express 1, 035603 (2014), arXiv:1405.2556.