Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 34: Poster Session - Topological Insulators

O 34.1: Poster

Monday, March 16, 2020, 18:15–20:00, P1C

Dirac-like Electrons in a Two-Dimensional Indium Layer on SiC(0001) — •Maximilian Bauernfeind¹, Jonas Erhardt¹, Philipp Eck², Victor Rogalev¹, Jörg Schäfer¹, Domenico Di Sante², Giorgio Sangiovanni², and Ralph Claessen¹ — ¹Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany — ²Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany

Mono- and sub-monolayer of In deposited on semiconducting or insulating substrates show a wide range of different surface reconstructions with unique electronic configurations. So far, none of them has been demonstrating Dirac-like electrons. Here we report first experimental results of an In (1×1) phase on SiC(0001) which clearly exhibits a linear band dispersion with Dirac points at the K/K’ points in the hexagonal Brillouin zone in angle-resolved photoelectron spectroscopy (ARPES). Density functional theory (DFT) gives a remarkably good agreement and predicts a topologically non-trivial gap of approximately 50 meV at the K points rendering it applicable for room temperature devices. A sensitive parameter in DFT is the bonding distance between the In layer and the substrate which determines the non-trivial topology of this system. Additionally, the stabilization of the In layer on SiC leads to the surface Rashba effect and causes a large splitting of the valence band at the K points with strong out-of-plane spin polarization as predicted by theory.