Seminar: Measuring and tuning the interlayer van der Waals interactions in 2D materials their heterostructures

Speaker：高扬研究员（浙江大学航空航天学院应用力学研究所）

Time:        2:00pm, Sept. 28, 2020 (Monday)

Place:       East Bulg. 4, Room 242, Zijingang Campus

Abstract

二维材料层间范德华力的测量与调控

Measuring and tuning the interlayer van der Waals interactions in 2D materials their heterostructures

Two-dimensional (2D) materials and their vertical heterostructures hold great promises for various scientific and technological applications. They are usually referred as van der Waals (vdW) materials, since vdW interactions between the layers create the extreme structural anisotropy and give rise to many extraordinary properties. This presentation introduces some of the most recent progress on the measurements and tuning of the interlayer vdW interactions in 2D materials and their heterostructures. The first section reports on an atomic force microscopy (AFM) based methodology – Angstrom indentation (Å-I) which can apply Å-scale deformation on 2D materials and precisely characterize the vdW interactions. A pressure-driven bilayer graphene to monolayer diamond structure phase transition can be induced and characterized by Å-I. The second part presents the band engineering of large-twist-angle graphene/h-BN moiré superlattices via diamond anvil cell. High pressure enhances the vdW interactions in the moiré superlattices, thus further broadening the primary bandgap and re-opening the secondary gap in the valence band in the imperfectly aligned system.

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