Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 91: 2D materials beyond graphene: TMDCs, silicene and relatives III

O 91.2: Talk

Thursday, March 15, 2018, 10:45–11:00, MA 043

Structural vs Electronic Effects in the Moiré Pattern of MoS₂ on Au(111) — •Daniela Dombrowski^1,2, Caio Silva¹, Nicolae Atodiresei³, Wouter Jolie^1,2, Ferdinand Farwick zum Hagen², Pardeep Thakur⁴, Vasile Caciuc³, Thomas Michely², Stefan Blügel³, Tien-Lin Lee⁴, and Carsten Busse^1,2,5 — ¹Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany — ²II. Physikalisches Institut, Universität zu Köln, Germany — ³Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Germany — ⁴Diamond Light Source, United Kingdom — ⁵Department Physik, Universität Siegen, Germany

Scanning tunneling microscopy (STM) measurements of molybdenum disulfide (MoS₂) grown on Au(111) show a strong corrugation of the moiré pattern, arising from the lattice mismatch between the MoS₂ layer and the underlying gold substrate. However, STM measurements do not give a pure structural information, since the tip follows the contour of a constant density of states. We combine low temperature scanning tunneling spectroscopy (STS) and x-ray standing wave (XSW) measurements with density functional theory calculations (DFT) to separate structural and electronic contributions to the moiré modulation. Our XSW measurements indicate that MoS₂ on gold is nearly flat in agreement with DFT calculations, giving a corrugation of 0.3 Å. In STS measurements we observe a significant shift of the valence band edge, following the moiré periodicity. This suggests that the observed corrugation in STM has mainly an electronic nature.