报告题目 (Title)：Stacking and Twisting of Layered Materials Enabled by Screw Dislocations and Non-Euclidean Surfaces
报告人 (Speaker)：赵宇舟 研究员（上海科技大学）
报告时间 (Time)：2025年12月9日（周二）9:30
报告地点 (Place)：宝山校区G601 & #腾讯会议：393-268-580
邀请人(Inviter)：陈宇戈
主办部门：量子科技研究院/理学院物理系
报告摘要：
The rise of van der Waals layered materials such as graphene and transition-metal dichalcogenides open up enormous opportunities for exploring novel quantum phenomena at the two-dimensional atomic limit. The physical properties of van der Waals materials are often affected by the symmetry of the crystal lattices. For example, breaking the inversion symmetry can lead to a variety of phenomena, such as second-harmonic generation, valley polarization, and ferroelectricity. The symmetry and symmetry breaking of layered materials are determined by the atomic arrangements within the layer and the layer stackings. Furthermore, different van der Waals layered materials can also be stacked vertically to create artificial new structures. In such stacked structures, the interlayer twist angle between stacked layers results in the formation of large-scale moiré superlattices that manipulate the electronic structures of van der Waals materials and provide an additional degree of freedom for tuning their physical properties. The stacking and twisting of layered materials lead to observations of new phenomena.
In this talk, I will introduce screw-dislocation-driven growth and showing its generality in the crystal growth of layered materials, discuss how the unique structures of screw dislocations influence the stacking and symmetry of layered materials. Moreover, I will highlight how screw dislocations enable interlayer twisting through the Eshelby twist mechanism and the non-Euclidean twist mechanism, which leads to exotic physical properties.
