Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 34: Poster Session - Topological Insulators
O 34.5: Poster
Monday, March 16, 2020, 18:15–20:00, P1C
Combined AFM/STM investigation of the topological insulators Bi2Se3 and TlBiSe2 — •Adrian Weindl, Felizitas Luisa Kolb, Alexander Liebig, and Franz J. Giessibl — Institute of Experimental and Applied Physics, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
Topological insulators (TIs) are a class of materials whose bulk system is insulating, whereas the surface houses topologically-protected metallic states. This enables investigation of the surface via scanning tunneling microscopy (STM). The observed structure of the conducting surface states depends on the atomic structure of the surface and can be influenced by introduction of magnetic perturbations as demonstrated on the materials Bi2Se3 and Bi2Te3 [1,2]. After cleaving in vacuum, the surface of the TI TlBiSe2 is terminated by half a monolayer of Tl atoms [3], which leads to the absence of a trivial surface state that was predicted for a completely filled Tl layer on the surface [4]. Simultaneous STM and atomic force microscopy (AFM) measurements on TlBiSe2 yielded very distinct results. While in the STM images, the conducting surface states had a worm-like structure, atomic resolution of the surface atoms was possible in AFM [3]. Here, we evaporate single iron atoms onto the surfaces of Bi2Se3 and TlBiSe2 to study the connection between surface structure, magnetic perturbations and electronic properties of TIs by a combination of AFM and STM measurements. [1] J. Honolka et al., PRB 108, 256811 (2012) [2] T. Eelbo et al., PRB 89, 104424 (2014) [3] F. Pielmeier et al., New J. Phys. 17, 023067 (2015) [4] B. Singh et al., PRB 93, 085113 (2016)