SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Poster Session V: 2D Materials: Electronic structure, excitations, etc. I
O 66.8: Poster
Mittwoch, 3. März 2021, 10:30–12:30, P
Mechanism of Self-Intercalation in Niobium Disulphide Monolayers on Gr/Ir(111) — •Daniela Mohrenstecher1, Timo Knispel1, Carsten Speckmann2, Jeison Fischer1, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany — 2Physics of Nanostructured Materials, University of Vienna, 1090 Wien, Austria
For 2D layered TMDCs the intercalation of native metal atoms into the van-der-Waals gap under metal excess conditions is a well-known phenomenon [1] and may result in covalently bonded materials that may exhibit phenomena like ferromagnetic order or spin-frustrated Kagome lattices [2].
Here we report self-intercalation for in-situ grown NbS2 monolayers on Gr/Ir(111) .The process utilizes Nb atoms that are already present in the material and traverse from the pristine material into the van-der-Waals gap between NbS2 and graphene during post-growth annealing.
Our quantitative coverage analysis based on scanning tunneling microscopy images indicates a conversion of Nb from the pristine material into the intercalated phase containing a stoichiometry of Nb5/3S2, featuring a √3×√3 R30∘ superstructure. Moreover, self-intercalation suppresses the charge density wave of the NbS2 monolayer. Using tunneling spectroscopy dramatic changes are found in the electronic structure self-intercalated compared to pristine non-intercalated layers.
[1] Jellinek et al. Nature 185, 376 - 377 (1960)
[2] Zhao et al. Nature 581 171-177 (2020)