Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 84: Electronic Structure of Surfaces I: Spectroscopy, Surface States

O 84.6: Vortrag

Donnerstag, 21. März 2024, 11:45–12:00, MA 144

Exploring the topologically dark surface of a layered weak 3D topological insulator — •Johannes Heßdörfer^1,2, Maximilian Ünzelmann^1,2, Eduardo Carillo-Aravena^2,3, Armando Consiglio^2,4, Michael Ruck^2,3, Domenico Di Sante⁵, and Friedrich Reinert^1,2 — ¹Experimentelle Physik VII, Universität Würzburg, Germany — ²Würzburg-Dresden Cluster of Excellence ct.qmat, Germany — ³Anorganische Chemie II, Technische Universität Dresden, Germany — ⁴Theoretische Physik I, Universität Würzburg, Germany — ⁵University of Bologna, Italy

Weak three-dimensional (3D) topological insulators (TI) can be considered as a stack of 2D TIs separated by insulating spacer layers. In the family of Bi₁₄Rh₃I₉ based [1] weak TIs, the electronic properties can be modified by altering the spacer layer through substitution. Here, we investigate the compound Bi₁₂Rh₃Ag₆I₉, by means of photoemission experiments and density functional theory band structure calculations. The results indicate the presence of surface states within the projected bulk band gap of the topologically dark surface which might alter the topological properties there. These states can be assigned to originate from the two different types of layer terminations. By analyzing the I 4d peak in the X-ray core level spectra, we show how the surface termination can be controlled, e.g. by the cleaving temperature.

[1]Rasche et al., Nat. Mater, 12, 422-425 (2013)

Keywords: TI; ARPES; XPS; Surface States