title: Hyperdislocations in van der Waals Layered Materials.
abstract: Dislocations are one-dimensional line defects in three-dimensional crystals or periodic structures. It is common that the dislocation networks made of interactive dislocations be generated during plastic deformation. In van der Waals layered materials, the highly anisotropic nature facilitates the formation of such dislocation networks, which is critical for the friction or exfoliation behavior for these materials. By transmission electron microscopy analysis, we found the topological defects in such dislocation networks can be perfectly rationalized in the framework of traditional dislocation theory, which we applied the name "hyperdislocations". Due to the strong pinning effect of hyperdislocations, the state of exfoliation can be easily triggered by 1° twisting between two layers, which also explains the origin of disregistry and frictionlessness for all of the superlubricants that are widely used for friction reduction and wear protection.
authors.affiliation: IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Korea.|Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Thuc Hue
authors.initials: TH
authors.lastname: Ly
authors.affiliation: IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Korea.|Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Korea.|Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Keum
authors.affiliation: School of Physics and Electronic Electrical Engineering, Huaiyin Normal University , Huai'an 223001, China.
authors.forename: Qingming
authors.initials: Q
authors.lastname: Deng
authors.affiliation: School of Materials Science and Engineering, Xiamen University of Technology , Xiamen 361024, China.|Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University , Beijing 100084, China.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Yu
authors.affiliation: IBS Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science, Sungkyunkwan University , Suwon 440-746, Korea.|Department of Energy Science, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
keywords: Hyperdislocation; TEM; superlubricity; transmission electron microscopy; vdW layered materials