Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Poster Monday: Nanostructures

O 18.7: Poster

Montag, 1. April 2019, 17:45–20:00, Poster F

Highly Ordered Metallic Phase of Indium on SiC(0001) — Maximilian Bauernfeind, •Jonas Erhardt, Jörg Schäfer, and Ralph Claessen — Physikalisches Institut and Röntgen Research Center for Complex Material Systems, Universität Würzburg, D-97074 Würzburg, Germany

For the monolayer growth of two-dimensional topological insulators (2D-TIs) on the insulating SiC(0001) substrate, the strong interaction between the deposited layer and the substrate dangling bonds (DBs) plays a pivotal role and drastically affects the electronic structure of the system. Especially 2D-TIs with fragile topology, e.g. quasi-freestanding stanene, require a passivated substrate to cancel out such interactions that are detrimental for the topological properties [1]. Indium with its three valence electrons is such a passivation candidate and leads to metallic or insulating phases on various semiconducting surfaces. Here we report first results of a highly ordered indium phase on SiC(0001). Scanning tunneling microscopy (STM) reveals a Kagome-like superstructure with a lattice constant of approximately 2.1 nm tentatively assigned as a (4√3 × 4√3)R30^∘ reconstruction. Additionally, scanning tunneling and angle-resolved photoelectron spectroscopy (STS and ARPES) show a band structure distinct from pristine SiC and reveal a metallic character with a pronounced electron pocket, indicative of a 2D electron gas. Interestingly, despite the large unit cell observed in STM and low-energy electron diffraction, the corresponding Brillouin zone is not effective in the ARPES band structure.

[1] D. Di Sante et al., arXiv:1807.09006 (2018)