Determining the interlayer shearing in twisted bilayer MoS2 by nanoindentation
Yufei Sun, Yujia Wang, Enze Wang, Bolun Wang, Hengyi Zhao, Yongpan Zeng, Qinghua Zhang, Yonghuang Wu, Lin Gu, Xiaoyan Li, Kai Liu
Abstract
Abstract The rise of twistronics has increased the attention of the community to the twist-angle-dependent properties of two-dimensional van der Waals integrated architectures. Clarification of the relationship between twist angles and interlayer mechanical interactions is important in benefiting the design of two-dimensional twisted structures. However, current mechanical methods have critical limitations in quantitatively probing the twist-angle dependence of two-dimensional interlayer interactions in monolayer limits. Here we report a nanoindentation-based technique and a shearing-boundary model to determine the interlayer mechanical interactions of twisted bilayer MoS 2 . Both in-plane elastic moduli and interlayer shear stress are found to be independent of the twist angle, which is attributed to the long-range interaction of intermolecular van der Waals forces that homogenously spread over the interfaces of MoS 2 . Our work provides a universal approach to determining the interlayer shear stress and deepens the understanding of twist-angle-dependent behaviours of two-dimensional layered materials.