Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 43: Poster Tuesday: Electronic Structure

O 43.6: Poster

Dienstag, 2. April 2019, 18:00–20:00, Poster D

A one-dimensional hole gas in monolayer MoS₂ — •Clifford Murray¹, Wouter Jolie^1,2, Joshua Hall¹, Arkady Krasheninnikov^3,4, Carsten Busse^1,2,5, Hannu-Pekka Komsa³, and Thomas Michely¹ — ¹II. Physikalisches Institut, Universität zu Köln, Germany — ²Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany — ³Department of Applied Physics, Aalto University School of Science, Aalto, Finland — ⁴Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — ⁵Department Physik, Universität Siegen, Germany

We epitaxially grow high-quality monolayer molybdenum disulfide (ML-MoS₂) on graphene on Ir(111), which is close to freestanding on this substrate [1]. We probe its electronic structure with low temperature scanning tunnelling spectroscopy.

The valence band is found to undergo stepwise bending at line defects such as 4|4E-type mirror twin boundaries (MTBs) and flake edges. Localised charge in these defects causes an upwards bending of the bands in the surrounding ML-MoS₂ semiconductor. This is experienced particularly strongly in the valence band, and leads to a 1D confinement of the charge carriers (holes) perpendicular to the defect. By contrast, the effect is not seen at 4|4P MTBs, the MTB type commonly present in the analogous MoSe₂ monolayer. We seek to understand and describe the observed behavior with the help of density functional theory.

[1] Hall, J. et al., 2D Mater. 5, 025005 (2018)