tailieunhanh - Báo cáo hóa học: " Dynamics of mechanical waves in periodic graphene nanoribbon assemblies"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Dynamics of mechanical waves in periodic graphene nanoribbon assemblies | Scarpa et al. Nanoscale Research Letters 2011 6 430 http content 6 1 430 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Dynamics of mechanical waves in periodic graphene nanoribbon assemblies Fabrizio Scarpa1 Rajib Chowdhury2 Kenneth Kam1 Sondipon Adhikari2 and Massimo Ruzzene3 Abstract We simulate the natural frequencies and the acoustic wave propagation characteristics of graphene nanoribbons GNRs of the type 8 0 and 0 8 using an equivalent atomistic-continuum FE model previously developed by some of the authors where the C-C bonds thickness and average equilibrium lengths during the dynamic loading are identified through the minimisation of the system Hamiltonian. A molecular mechanics model based on the UFF potential is used to benchmark the hybrid FE models developed. The acoustic wave dispersion characteristics of the GNRs are simulated using a Floquet-based wave technique used to predict the pass-stop bands of periodic mechanical structures. We show that the thickness and equilibrium lengths do depend on the specific vibration and dispersion mode considered and that they are in general different from the classical constant values used in open literature nm for thickness and nm for equilibrium length . We also show the dependence of the wave dispersion characteristics versus the aspect ratio and edge configurations of the nanoribbons with widening band-gaps that depend on the chirality of the configurations. The thickness average equilibrium length and edge type have to be taken into account when nanoribbons are used to design nano-oscillators and novel types of mass sensors based on periodic arrangements of nanostructures. PACS Introduction Graphene nanoribbons GNRs 1 have attracted a significant interest in the nanoelectronics community as possible replacements to silicon semiconductors quasi-THz oscillators and quantum dots 2 . The electronic state of GNRs depend .