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TT: Fachverband Tiefe Temperaturen

TT 45: 2D Materials: Electronic Structure and Exitations III (joint session O/HL/TT)

TT 45.3: Talk

Thursday, March 20, 2025, 11:00–11:15, H11

Influence of Edge Termination on the Electronic Structure of Single Layer MoS₂ on Graphene/Ir(111) — •Alice Bremerich¹, Marco Thaler², Thais Chagas¹, Borna Pielic¹, Laerte Patera², and Carsten Busse¹ — ¹Universität Siegen, Deutschland — ²Universität Innsbruck, Österreich

MoS₂ is the prototypical semiconducting single-layer transition-metal dichalcogenide (TMDC). It exhibits a metallic edge state that induces partial charge accumulation at its edges, resulting in band bending effects. This 1D state acts as a barrier to electron transport across the edge and contributes significantly to quantum confinement effects in TMDC islands. In this study, we tune the edge state and the associated band bending by altering the edge termination of MoS₂/gr/Ir(111) and investigate the resulting changes in the electronic structure by Scanning Tunneling Microscopy and Spectroscopy (STM and STS) at 8 K.

Quasi-freestanding MoS₂ is grown on gr/Ir(111) by Molecular Beam Epitaxy (MBE). We prepare hexagonal islands that exhibit two geometrically different edge types (Mo- and S-type). We vary the chemical potential of sulfur and thereby modify the chemical environment of the boundaries. The partial charge at the perimeter depends on edge type as well as edge chemistry. In consequence, also the upward bending of both valence and conduction band shows distinct variations.

Keywords: Scanning Tunneling Spectroscopy; Transition Metal Dichalcogenide; Metallic Edge State