Friction Anisotropy of MoS2: Effect of Tip–Sample Contact Quality
| Autor: | Ashlie Martini, Robert W. Carpick, Mohammad R. Vazirisereshk, Kathryn Hasz |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Condensed matter physics 02 engineering and technology Crystal structure 021001 nanoscience & nanotechnology Symmetry (physics) Molecular dynamics 020303 mechanical engineering & transports Quality (physics) 0203 mechanical engineering Monolayer General Materials Science Physical and Theoretical Chemistry 0210 nano-technology Anisotropy Nanoscopic scale Asperity (materials science) |
| Zdroj: | The Journal of Physical Chemistry Letters. 11:6900-6906 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.0c01617 |
| Popis: | Atomic-scale friction measured for a single asperity sliding on 2D materials depend on the direction of scanning relative to the material's crystal lattice. Here, nanoscale friction anisotropy of wrinkle-free bulk and monolayer MoS2 is characterized using atomic force microscopy and molecular dynamics simulations. Both techniques show 180° periodicity (2-fold symmetry) of atomic-lattice stick-slip friction vs. the tip's scanning direction with respect to the MoS2 surface. The 60° periodicity (6-fold symmetry) expected from the MoS2 surface's symmetry is only recovered in simulations where the sample is rotated, as opposed to the scanning direction changed. All observations are explained by the potential energy landscape of the tip-sample contact, in contrast with nanoscale topographic wrinkles that have been proposed previously as the source of anisotropy. These results demonstrate the importance of the tip-sample contact quality in determining the potential energy landscape and, in turn, friction at the nanoscale. |
| Databáze: | OpenAIRE |
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