SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 82: Graphene I: Adsorption, Intercalation and Doping
O 82.9: Vortrag
Donnerstag, 30. März 2023, 17:00–17:15, GER 37
Magnetotransport and structural properties of Bi(110) islands on epitaxial graphene — •Julian Koch1, Sergii Sologub1,2, Chitran Ghosal1, and Christoph Tegenkamp1 — 1Institut für Physik, TU Chemnitz, Reichenhainerstr. 70, 09126 Chemnitz — 2Institute of Physics, NAS of Ukraine, Nauki avenue 46, 03028 Kyiv
Magnetotransport measurements at 10 K using a 4 T magnet were performed on Bi islands on monolayer graphene/SiC with average thickness up to 3.6 bilayers (BL). They are supported by structural investigations using SPA-LEED and STM, which reveal that Bi predominately grows as needle-like islands with a (110) termination.
The analysis of the magneto and Hall conductivity gives the electron concentration and the mobility. The electron concentration slightly decreases with 4·1011 cm−2BL−1 from an initial value of 1.4·1013 cm−2 for the clean surface. The mobility decreases from 2100 cm2V−1s−1 to a minimal value of 1630 cm2V−1s−1 at 2.4 BL. Moreover, the electron electron interaction contribution to the magneto conductivity, which is almost negligible for the clean surface, strongly increases linearly with approximately 0.44 mS/BL. At 3.6 BL it is equal to approximately half the Drude conductivity at zero field.
The weak localization (WL) of the clean surface gradually transitions to weak anti-localization (WAL) with increasing Bi coverage. This is associated with a decrease of the dephasing length of the scattered electrons, which is correlated with the average distance of the islands obtained from STM measurements.