Twist-dependent interlayer friction measurements using cantilevers covered with two-dimensional materials

We demonstrate interlayer friction measurements between two-dimensional (2D) materials, using cantilevers covered with 2D flakes. The interlayer friction between 2D flakes on the cantilever and a substrate was measured by utilizing lateral force microscopy (LFM). The cantilever was prepared by using focused ion beam (FIB) and dry transfer techniques. Pt pyramid was built on a tipless cantilever by FIB deposition [1] and 2D flakes were transferred on the Pt pyramid by using a dry transfer method. When we carried out LFM on a graphene flake on a SiO₂/Si substrate using the cantilever covered with graphene, we got a clear LFM image of the graphene flake on the substrate, reflecting the difference of the friction of graphene and SiO₂ against graphene on the cantilever. Furthermore, when we changed the interlayer twist angles between the graphene layers on the cantilever and the substrate by rotating the graphene on the substrate, the interlayer friction showed a twist angle dependence which has a period of ~60 degrees. This is consistent with the interlayer friction property between graphene layers where the interlayer friction is expected to become maximum in commensurate conditions whose period is 60 degrees [2]. Those results suggest that our technique can become a new way to characterize twist-dependent interlayer friction properties between 2D materials including van der Waals heterostructures.

[1] A. Inbar et al., Nature 614, 682 (2023).

[2] M. Dienwiebel et al., Phys. Rev. Lett. 92, 126101 (2004).