Science ( IF 41.845 ) Pub Date : 2020-07-31 , DOI: 10.1126/science.abd4527 Xiaodong Han
Van der Waals (vdW) materials are made up of strongly bonded two-dimensional (2D) layers that are bound in the third dimension through weaker dispersion forces. Graphite is a vdW material broadly used in industry in electrodes, lubricants, fibers, heat exchangers, and batteries. Its single-layer form, graphene (1), ushered in the new era of 2D materials that have tunable thickness and bandgap, as well as electronic confinement effects (2). Although these thin materials are inherently flexible (3), most vdW materials other than silver sulfide (Ag2S) (4) are intrinsically brittle in their bulk form, which can limit how they are processed, as well as their applications. On page 542 of this issue, Wei et al. (5) report that indium selenide (InSe), in its single-crystalline form, exhibits exceptional plasticity under compressive stress.