Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 46: 2D Materials beyond Graphene: TMDCs, Slicene and Relatives

O 46.9: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Epitaxial growth of Sn on SiC(0001): A study by scanning tunneling microscopy — •Felix Reis, Maximilian Bauernfeind, Ralph Claessen, and Jörg Schäfer — Physikalisches Institut, Universität Würzburg

This work is motivated by the unusual properties of graphene, which was the first material predicted to show the quantum spin Hall effect based on its spin-polarized topological edge states, which are located in the bulk energy gap. However, this gap is very small (order of µeV), such that it is impossible to access the edge channels in experiment.

One approach to overcome this problem is to pursue the realization of honeycomb lattices with high-Z atoms. A material that received great attention by theoretical modeling is (free-standing) stanene, made of Sn atoms and predicted to have a significantly larger bandgap due to stronger spin-orbit interaction [1]. However, a substrate – as needed for real-world experiments – had not been considered.

Here we report on the epitaxial growth of Sn reconstructions on SiC(0001) in the regime of around one monolayer coverage. The structures are examined by scanning tunneling microscopy (STM) and low-energy electron diffraction. We observe the formation of long-range ordered Sn-induced atomic lattices. Interestingly, depending on the coverage, these exhibit (3× 3) or (6√3×√3) superstructures, respectively. Close-up inspection is suggestive of hexagonal structural units. We will present a detailed analysis of the STM results, and discuss these in the light of theoretical predictions.

[1] Y. Xu et al., Phys. Rev. Lett. 111, 136804 (2013).