Structural and electronic bistability in ZnS single sheets and single-walled nanotubes

摘要

We investigate a single sheet graphene analogue and a single-walled nanotube of ZnS using electronic structure calculations. Unlike the nearly perfectly flat structures of graphene and graphene analogues of other binary compounds (e.g., BN, ZnO, SiC), ZnS sheets are predicted to attain higher stability as complex, radically reconstructed structures. This predisposition to reconstruct also persists when ZnS sheets are rolled up into single-walled nanotubes. Smooth nanotubes and fiat single sheets of ZnS have significantly smaller band gaps than their reconstructed counterparts, and are found to be metastable minima that are accessible from the reconstructed structures via external strain. This bistable electromechanical coupling may have significant technological potential (e.g., nanosensors, optomechanical switches).