Makk Péter (BME Fizikai Intézet, "Korrelált van der Waals struktúrák" Lendület Csoport)

Building and tuning of van der Waals heterostructures

Az előadás kivonata: Graphene is the wonder material: it is strong, it has ultra-high mobility, and it has a special band structure, which makes it interesting for fundamental research. The properties of graphene can also be engineered by combining it with other 2D materials using van der Waals stacking – like putting bricks of LEGO on top of each other [1]. There are quite many building blocks available now: semiconductors, superconductor, magnetic and materials with larger spin-orbit interaction. The combination of these can lead to novel phases from gate tunable magnets to topological superconductors. Moreover, one can also go beyond, what can be done in LEGO: these materials can be placed on top of each other under any rotation angle – therefore this field is called twistronics [2]. For special, “magic” rotation angles novel correlated and topological phases formed. Since in these structures the layer distance strongly affects the interaction between the layers, pressure is an ideal tool to engineer the band structure of van der Waals materials.

In this talk I will show how the bandstructure of van der Waals materials can be engineered by placing different 2D materials on top of each other, by twisting them or by using pressure [3-6]. Using electrical transport measurements, I will show that a spin orbit coupling in graphene can be generated by placing another material next by, and also demonstrate how the magnetic state of 2D magnets can be tuned using pressure.

[1] K. S. Novoselov et al., Science 353, 6298 (2016).
[2] Nature Physics, 16, 725 (2020).
[3] B. Fülöp et al., Journal of Appl. Phys., 130, 064303 (2021).
[4] B. Fülöp, A. Márffy, S. Zihlmann, M. Gmitra, E. Tóvári, B. Szentpéteri, M. Kedves, K. Watanabe, T. Taniguchi, J. Fabian, C. Schönenberger, P. Makk, Sz. Csonka, npj 2D Materials and Applications 5, 82 (2021).
[5] M. Kedves et al., Nano Letters, 10.1021/acs.nanolett.3c03029 (2021).
[6] B. Szentpéteri, P. Rickhaus, F. K. de Vries, A. Márffy, B. Fülöp, E. Tóvári, K. Watanabe, T. Taniguchi, A. Kormányos, Sz. Csonka, and P. Makk, Nano Letters, 21, 8777 (2021).

Az előadóról:

• Google Scholar
• Curriculum Vitae