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HL: Fachverband Halbleiterphysik

HL 116: Topological insulators (organized by MA)

HL 116.1: Vortrag

Freitag, 4. April 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.