Dresden 2020 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 47: Poster Session - 2D Materials: Electronic Structure, Excitations, etc.
O 47.15: Poster
Dienstag, 17. März 2020, 18:15–20:00, P2/EG
Metal insulator transition studied with transport on H on epitaxial graphene — •Diana Slawig1, Markus Gruschwitz2, and Christoph Tegenkamp1,2 — 1Leibniz Universität Hannover, Germany — 2TU Chemnitz, Germany
The ability of atomic hydrogen to chemisorb on graphene makes it a quite interesting system for hydrogen storage and sensor applications. The introduction of scattering centers via atomic hydrogen chemisorption, the concomitant spin polarization and the opening of a bandgap due to symmetry breaking of the sublattice symmetry makes it particularly interesting for electronic transport measurements.
In this study we performed systematic transport investigations on hydrogen adsorption on epitaxial monolayer graphene on SiC by means of 4-tip STM/SEM. Conductance values were investigated for various surface H-coverages up to the saturation coverage of 0.4 ML, well below the percolation limit. As a function of the H coverage, we observed a metal-insulator transition. Thereby, the sheet resistance increases by three orders of magnitude up to 37 kΩ . Temperature dependent measurements on these hydrogen terminated graphene show activated transport behavior with an activation energy of 30 meV. We suspect that upon adsorption of the saturation coverage, the monolayer is neutralized and gapped due charge transfer and breaking of the lattice symmetry.