Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: 2D Materials III: Nanomembranes, hBN, and Particle Interactions
O 59.9: Vortrag
Mittwoch, 3. April 2019, 17:15–17:30, H16
Characterization of interlayer forces in 2D heterostructures using neutral atom scattering — •Amjad Al Taleb1,2, Gloria Anemone1, Rodolfo Miranda1,2,3,4, and Daniel Farías1,3,4 — 1Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Spain — 2Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Madrid, Spain — 3Instituto `Nicolás Cabrera', Madrid, Spain — 4Condensed Matter Physics Center (IFIMAC), Madrid, Spain
We show that neutral atom scattering is suitable to determine the coupling strength between a two-dimensional (2D) material and the underlying substrate. This information can be obtained from the thermal attenuation of the specular intensity, as well as from angular distributions of He and Ne atoms in the low incident energy (20-50 meV) regime. For graphene (Gr) grown on several metal substrates, there is a direct correlation between the slope of thermal attenuation measurements and the Gr-substrate coupling strength obtained from surface phonons measurements. In addition, Ne scattering presents a broad, classical angular distribution when the Gr-substrate coupling is weak, like in Gr/Ir(111), whereas sharp diffraction features are observed for strongly interacting systems, like Gr/Ru(0001). The influence of the moiré superstructures on this simple picture is also discussed. This superstructures induces a splitting of the flexural mode of Gr in addition of additional phonon dispersion lines as a result of Umklapp scattering. We show evidence of the localization of the phonon modes from the difference in their thermal attenuation behaviors.