Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: 2D Materials IV: Charge Density Waves and Electronic Properties
O 87.1: Vortrag
Donnerstag, 4. April 2019, 15:00–15:15, H25
The 3 × 3 charge density wave in quasi-freestanding monolayer 2H-TaS2 — •Joshua Hall1, Camiel van Efferen1, Clifford Murray1, Matthias Rolf1, Niels Ehlen1, Jun Li1, Jan Berges2, Erik van Loon2, Tim Wehling2, Alexander Grüneis1, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut für Theoretische Physik, Bremen Center for Computational Materials Science, Universität Bremen, Germany
We report on the 3 × 3 charge density wave (CDW) in a quasi-freestanding monolayer of TaS2, as grown by molecular beam epitaxy on graphene on Ir(111) [1].
Investigated by scanning tunnelling microscopy, the 3 × 3 periodicity of the CDW is visible at liquid helium temperatures, and allows analysis of spatial CDW amplitude variations and the influence of point and line defects. Performing low temperature scanning tunnelling spectroscopy (STS) reveals a decreased density of states at the Fermi energy, indicating partial gapping of the Fermi surface.
In constant current STS maps, an energy dispersive standing wave pattern is found, which firstly illustrates the quasi-freestanding nature of the TaS2 islands and secondly allows partial determination of the band structure, which is compared to data from angle resolved photoemission spectroscopy of the same system.
[1] Hall et al., 2D Materials 5 025005 (2018)