Regensburg 2022 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: Poster

DS 20.8: Poster

Wednesday, September 7, 2022, 16:00–18:00, P3

Structural and electronic investigations of Bismuth multilayers with DFT — •Fabian Teichert¹, Chitran Ghosal¹, Uwe Gerstmann², Christoph Tegenkamp¹, and Angela Thränhardt¹ — ¹Institute of Physics, Chemnitz University of Technology, Chemnitz, Germany — ²Department of Physics, Paderborn University, Paderborn, Germany

Bismuth shows a variety of interesting properties as bulk material but also as thin film, e.g. it is a topological insulator, shows strong spin-orbit coupling effects and has a semimetal-semiconductor transition concerning film thickness. The focus of this presentation will be on density functional theory (DFT) calculations, which have been done for Bi(110) multilayers to get insights into the concrete structure and electronic states. We compare the results with Bi multilayers, which have been grown epitaxially on graphene substrate and where (110) slabs have been figured out. They are treated with scanning tunneling microscopy (STM) measurements for various slab thicknesses. We found an even/odd scheme concerning the number of monolayers as well as concerning the number of bilayers indicating a structural relaxation like the black phosphorus allotrope. Further calculations with graphene and highly oriented pyrolytic graphite (HOPG) substrate have be performed to figure out if structurally separated and electronically decoupled layers are present at the substrate interface. Concerning the electronic properties, we present the calculated bandstructures and density of states and comparisons with the measured differential conductance, which are in good agreement.