Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 90: 2D Materials VI: Growth, Structure and Substrate Interaction
O 90.2: Vortrag
Donnerstag, 21. März 2024, 15:15–15:30, MA 005
Incommensurability and negative thermal expansion of single layer hexagonal boron nitride — •Marko Kriegel1, Karim Omambac1, Steffen Franzka2, Frank Meyer zu Heringdorf1,2, and Michael Horn-von Hoegen1 — 1Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany — 2Interdisciplinary Center for Analytics on the Nanoscale (ICAN), Carl-Benz-Str. 199, 47057 Duisburg, Germany
The emerging field of straintronics, i.e., the control and utilization of the strain state of a 2D material, is of great importance for their technological development, specifically in view of their future incorporation into van der Waals heterostructures. To gain fundamental insights into structural peculiarities of two-dimensional systems, single layer hexagonal boron nitride (hBN) grown on Ir(111) by chemical vapor deposition was used as a prototypical model system: High-resolution reciprocal space mapping by SPA-LEED reveals the incommensurate nature of the material system by measuring the hBN in-plane lattice parameter, facilitated by the moiré magnification effect. In a growth temperature (Tg) regime of 700-1150 ∘C an average lattice parameter of 2.496±0.006 Å was found. Eventually, careful disentanglement of the hBN’s and substrate’s behavior for rising Tg allowed the determination of a negative thermal expansion coefficient of αhBN = -2.4 ± 1.2× 10−6 K−1.[1]
[1] *M. Kriegel et al. Appl. Surf. Sci. 624 (2023) 157156
Keywords: 2D hexagonal Boron Nitride; Study of in-plane lattice parameter; Incommensurability of 2D hBN on Ir(111); Negative thermal expansion of freestanding hBN