SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 82: Graphene I: Adsorption, Intercalation and Doping

O 82.2: Vortrag

Donnerstag, 30. März 2023, 15:15–15:30, GER 37

Sn-induced superstructures at the EG/SiC(0001) interface and their influence on EG — •Zamin Mamiyev, Chitran Ghosal, and Christoph Tegenkamp — Institut für Physik, Technische Universität Chemnitz

Intercalating chemical elements into the buffer layer/SiC(0001) interface is a promising approach to delaminate a single carbon layer forming extended epitaxial graphene (EG) layers with new properties. In this regard, Sn is an interesting candidate because the triangular monolayer structure on SiC(0001) was shown to exhibit a Mott state [1].

By means of low energy electron diffraction we studied recently in detail the intercalation of Sn below the buffer layer grown before on SiC(0001) and found 1×1 and (√3×√3) Sn induced phases depending on details of the annealing procedure [2]. As deduced from transport but also local spectroscopy, the former is metallic while the latter reveals a band gap opening. In addition, we found a (√3×√3)R30^∘ interference pattern with respect to the EG lattice. This so-called broken Kekulé order forms due to the breaking of the bond order in EG and often found in the vicinity of buckled Sn(1×1) subsurface clusters opening the channel for K,K’ scattering in EG. The electronic structure and, in particular, the formation of a Mott gap will be investigated by electron energy loss spectroscopy.

[1] S. Glass et al., PRL 114, 247602 (2015). [2] Z. Mamiyev and C. Tegenkamp, Surf. & Int. 34, 102304 (2022).