Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 93: Topological Insulators (MA jointly with DS, HL, O, TT)
O 93.1: Talk
Friday, April 4, 2014, 09:30–09:45, HSZ 04
Experimental characterization and simulation of quasi-particle-interference in the Bi-bilayer topological insulator — •Matteo Michiardi1, Andreas Eich2, Gustav Bihlmayer3, Alex A. Khajetoorians2, Jens Wiebe2, Jianli Mi4, Bo B. Iversen4, Philip Hofmann1, and Roland Wiesendanger2 — 1Department of physics and astronomy, Aarhus University, Denmark — 2Institute of Applied Physics, University of Hamburg, Germany — 3Peter Grünberg Institut, Forschungszentrum Jülich, Germany — 4Center for Materials Crystallography, Aarhus University, Denmark
Topological insulators (TI) are a new class of materials that host gapless surface states with spin helicity. While several 3D TIs have been discovered, the interest in 2D TI systems that can host topological edge state is rising. A single bilayer of bismuth is predicted to be such a 2D TI. Here we present an experimental and theoretical study of a Bi-bilayer grown on 3D TI Bi2Se3. The use of Bi2Se3 as substrate allows the epitaxial growth of the bilayer in the rhombohedral structure, as shown by Scanning Tunnelling Microscopy. We calculate the band structure of the Bi-bilayer/Bi2Se3 system by Density Function Theory (DFT) and experimentally study the quasi particle interference (QPI) on the bilayer. In order to clarify the scattering channels responsible for the QPI, we perform simulations based on the Joint Density of States method starting from our DFT calculations. The comparison with the experimental results reveals a good match for a wide range of binding energies for both occupied and unoccupied states.