Contributed Speaker
Dr. Stefano Chiodini
Twisted hBN moiré superlattices probed by tapping mode AFM phase imaging
Stefano Chiodini¹, James Kerfoot², Giacomo Venturi¹, Sandro Mignuzzi², Eugene M. Alexeev², Barbara L. T. Rosa², Sefaattin Tongay³, Takashi Taniguchi⁴, Kenji Watanabe⁵, Andrea C. Ferrari², Antonio Ambrosio¹
¹ Center for Nano Science and Technology, Fondazione Istituto Italiano di Tecnologia, Via Rubattino 81, 20134, Milan, Italy
² Cambridge Graphene Centre, University of Cambridge, 9, JJ Thomson Avenue, Cambridge, CB3 0FA, UK
³ School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, USA
⁴ Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
⁵ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
When a twist angle is applied between two layered materials (LMs), the moiré superlattice spatially modulates the registry of the layers and the sample functional properties. Several works have recently explored the optical, [1] electric, [2] and electro-mechanical [3] moiré-dependent properties of such twisted LMs, but no direct visualization and quantification of van der Waals (vdW) interactions has been presented, so far. In this work, we show the application of tapping mode AFM phase imaging to probe the spatial modulation of vdW potential in twisted hBN moiré superlattices. [4] We find that a moiré superlattice is visualized in the phase channel only when non-contact (long-range) forces are probed, revealing the modulation of the vdW potential at the sample surface, following AB and BA stacking domains. Tapping mode AFM phase imaging is non-invasive, compatible with every environment and no sample perturbation is required. Some recent result on the (electro-) mechanical properties of t-hBN moiré patterns will also be discussed at the end of the talk. [5]
References
[1] S. L. Moore et al., Nat. Commun., 12, 5741 (2021)
[2] M. Stern et al., Science, 372 (2021)
[3] L. J. McGilly et al., Nat. Nanotechnol., 15, 580–584 (2020)
[4] S. Chiodini et al., ACS Nano 16, 7589-7604 (2022)
[5] S. Chiodini et al., arXiv:2406.02195 (2024)