SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 64: Poster: Graphene
O 64.4: Poster
Mittwoch, 29. März 2023, 18:00–20:00, P2/EG
Electronic magneto-transport in epitaxial graphene covered with Bi(110) islands — •Sergii Sologub1,2, Julian Koch2, Chitran Ghosal2, and Christoph Tegenkamp2 — 1Institute of Physics, NAS of Ukraine, Nauki avenue 46, 03028 Kyiv — 2Institut für Physik, TU Chemnitz, Reichenhainerstr. 70, 09126 Chemnitz
Magneto-conductance and Hall voltage of epitaxial graphene formed on SiC and covered with ultrathin Bi islands were measured within the range of ±4 T. The structure and morphology of Bi coverages of average thickness up to 4 bilayers, MBE-grown at RT as well as after-annealed, were determined by SPA-LEED and STM techniques. The coverage was found to consist of needle-like (110) islands with “magic” widths and thicknesses.
The analysis of the low-field part of the magneto-conductance reveals a transition from weak-localization (WL) to weak antilocalization (WAL) with increasing Bi coverage and allows to characterize the scattering of conduction electrons by determining electron scattering lengths, namely inelastic-dephasing, intervalley and intervalley symmetry breaking ones. The correlation of the average sizes of and distance between Bi(110) islands for different coverages with the characteristic lengths demonstrate the role of electron scattering on edges and within the islands in the WL-WAL transition. Calculated dependencies of Hall and magneto-resistance allow determining changes of the electron density induced by Bi adsorption and reveal the contribution of electron-electron interaction in electronic transport.