2014/01/04 by Ping-Heng Tan, Ping‐Heng Tan, Jiang-Bin Wu +9 · 1 citation
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Carbon Nanotubes in Composites #Composite material #Engineering #Fullerene Chemistry and Applications #Graphene #Graphene research and applications #Layer (electronics) #Materials science #Mechanical engineering #Nanotechnology #Scroll #Shear (geology) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.89.235404
14 pages, 5 figures
arxiv created 2014/01/04 · openalex publication_date 2014/06/06 · arxiv updated 2014/06/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The in-plane shear (C) modes between neighbor layers of 2-4 layer graphenes (2-4LGs) and the corresponding 2-4 layer graphene scrolls (2-4LGSs) rolled up by 2-4LGs at edges are investigated by Raman scattering. In contrast to the result that only one C mode is observed in 3-4LGs, all the C modes of 3-4LGs are observed in 3-4LGSs, whose frequencies agree with the theoretical prediction by the force-constant and linear chain models. The results indicate that the C mode intensity of 2-4LGSs is resonantly enhanced by the electronic transition gaps of band structures of 2-4LGS structures at edges, which makes it possible to observe all the C modes. Indeed, for a simple assumption, the calculated band structures of twisted (n+n)LGs (n=2,3,4) show parallel conduction and valence bands and the corresponding Van Hove singularities in the joint density of states along \ensuremathΓ-M, \ensuremathΓ-K and/or K-M directions. The intensity resonance of the C modes provides direct evidence to explain how the band structure of few layer graphenes can be sensitive to local stacking configurations. This result can be extended to n layer graphene (n>4) for understanding the basic phonon and electronic properties of multilayer graphenes. This observation of all the C modes in graphene scrolls can be foreseen in other two-dimensional materials with similar scroll structures.