Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 49: Metal Substrates III: Structure, Epitaxy and Growth

O 49.8: Vortrag

Mittwoch, 3. April 2019, 12:15–12:30, H5

Electronic and atomic structure of Bi(111) and anomalous behaviour after ion bombardment — •Kuanysh Zhussupbekov¹, Brian Walls¹, Andrey Ionov^1,2, Sergey Bozhko^1,2, Rais Mozhchil², Killian Walshe¹, and Igor Shvets¹ — ¹School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland — ²Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia

Defects in a surface crystal structure of layered materials lead to a local break of surface translational symmetry and can modify the surface states. In this work, Bi(111) surfaces cleaved at low temperature and ion etched are investigated by Low-Energy Electron Diffraction (LEED), X-ray Photoelectron Spectroscopy (XPS), Ultraviolet Photoelectron Spectroscopy (UPS), Scanning Tunneling Microscopy (STM) and Spectroscopy (STS) techniques. STM measurements on the Bi(111) crystal demonstrated different heights of the steps (mono- and bi-layered steps). Furthermore, STS revealed that these steps have slightly different electronic properties, likely correlated to the cleavage breaking covalent (mono-layer) vs Van der Waals (bi-layer) bonds. The Bi(111) surface after ion etching at 110 K and room temperature reveals anomalous behaviour of the surface crystal structure: it results in the formation of flat mono- and bi-layer terraces and surface periodicity as observed by LEED even after continuous ion sputtering. Analysis of the electronic density of states near the Fermi level measured by UPS did not observe a noticeable difference at the Fermi edge.