Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 99: 2D materials beyond graphene: TMDCs, silicene and relatives IV
O 99.4: Talk
Thursday, March 15, 2018, 15:45–16:00, MA 043
One-dimensional states confined within mirror twin boundaries in MoS2 — •Wouter Jolie1,2, Clifford Murray1, Philipp Weiß3, Joshua Hall1, Fabian Portner3, Nicolae Atodiresei4, Arkady Krasheninnikov5, Hannu-Pekka Komsa6, Achim Rosch3, Carsten Busse1,2,7, and Thomas Michely1 — 1Institute of Physics II, University of Cologne, Germany — 2Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany — 3Institute for Theoretical Physics, University of Cologne, Germany — 4Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Germany — 5Helmholtz-Zentrum Dresden-Rossendorf, Germany — 6Department of Applied Physics, Aalto University, Finland — 7Department Physik, Universität Siegen, Germany
We investigate epitaxial, single-layer MoS2 on graphene on Ir(111) with scanning tunneling microscopy and spectroscopy (STM/STS). We find a large bandgap of 2.50±0.05 eV in MoS2 showing that it is well decoupled from the substrate. The MoS2 islands feature two types of long, straight, highly symmetric mirror twin boundaries. Along these we measure a small bandgap of the order of 0.1 eV, together with periodic beatings in the local density of states. Using ab initio calculations, these features are traced back to one-dimensional metallic twin boundary states. We will critically discuss the contributions of confinement (finite wire length), Peierls instability (charge density wave formation) and spin-charge separation to explain the observed features.