Elastic properties of graphene flakes: Boundary effects and lattice vibrations

Abstract

We present a phenomenological theory together with explicit calculations of the electronic ground-state energy, the surface contribution, and the elastic constants ͑"Lamé parameters," i.e., Poisson ratio, Young's modulus͒ of graphene flakes on the level of the density-functional theory employing different standard functionals. We observe that the Lamé parameters in small flakes can differ from the bulk values by 30% for hydrogenated zigzag edges. The change results from the edge of the flake that compresses the interior. When including the vibrational zero-point motion, we detect a decrease in the bending rigidity, , by ϳ26%. The vibrational frequencies flow with growing N due to the release of the edge-induced compression. We calculate the corresponding Grüneisen parameters and find good agreement with previous authors.

Improved All-Carbon Spintronic Device Design

“…This rhombus GNF (RGNF) is still Kekuléan, and the reading and writing of spin information to such RGNFs has been theoretically demonstrated41, including an analysis of the structural properties42. By comparing these two structure families, we will see that not only are non-frustrated NOT gates viable, but we can also improve the magnetic coupling by keeping the connecting edges as zigzaged as possible.…”

Synthesis, Structure, and Properties of Graphene and Graphene Oxide

“…This observation implies that for improved mechanical properties of GO papers, the intersheet shear and tensile deformation should be reduced by cross-linking them using metal ions or functionalization. [225] 1.01 Ab initio computations [226] 1.05 Density functional theory [227] 1.05 First principles calculations [228] 1.01 MD and MM simulation [229] 1.05-1.09 Empirical force constant calculations [230] 1.13 Atomistic Monte Carlo simulations [231] 1.04 Continuum elasticity theory and tight-binding atomistic simulations [232] 0.92 Energetic model [233] 0.90 a Because the Young's modulus for a 2D sample is just force/length, elastic properties of graphene in some references are reported in N/m, which are converted to TPa by taking effective thickness as 0.34 nm. MD molecular dynamics, MM molecular mechanics…”

Adhesion and electronic structure of graphene on hexagonal boron nitride substrates

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