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O: Fachverband Oberflächenphysik

O 29: Poster: 2D Materials

O 29.31: Poster

Dienstag, 19. März 2024, 12:30–14:30, Poster A

Unveiling the nature of atomic defects in graphene on a metal surface — •Karl Rothe, Nicolas Néel, and Jörg Kröger — TU Ilmenau, Institut für Physik

Argon ion bombardment of graphene-covered Ir(111) induces two types of atomic-scale defects. Using a scanning tunneling microscope, both defects appear as a depression without discernible interior structure suggesting the presence of vacancy sites in the graphene lattice. With an atomic force microscope, however, only one kind of defect can be identified as a site with missing carbon atoms, while the other kind reveals an intact graphene sheet. Spatially resolved spectroscopy of the differential conductance and the measurement of short-range force variations as a function of the lateral and vertical probe-defect distance corroborate the different character of the defects. The tendency of the vacancy defect to form a chemical bond with the microscope probe is reflected by the strongest attraction at the vacancy center as well as by hysteresis effects in force traces recorded for tip approach to and retraction from the Pauli repulsion range of vertical distances.

Financial support by the Deutsche Forschungsgemeinschaft through Grant No. KR 2912/17-1 is acknowledged.

Keywords: Graphene; STM; AFM; Atomic Defects