Nature and strength of bonding in a crystal of semiconducting nanotubes: van der Waals density functional calculations and analytical results

Abstract

The dispersive interaction between nanotubes is investigated through ab initio theory calculations and in an analytical approximation. A van der Waals density functional (vdW-DF) [Phys. Rev. Lett. 92, 246401 (2004)] is used to determine and compare the binding of a pair of nanotubes as well as in a nanotube crystal. To analyze the interaction and determine the importance of morphology, we furthermore compare results of our ab initio calculations with a simple analytical result that we obtain for a pair of well-separated nanotubes. In contrast to traditional density functional theory calculations, the vdW-DF study predicts an intertube vdW bonding with a strength that is consistent with recent observations for the interlayer binding in graphitics. It also produce a nanotube wall-to-wall separation which is in very good agreement with experiments. Moreover, we find that the vdW-DF result for the nanotube-crystal binding energy can be approximated by a sum of nanotube-pair interactions when these are calculated in vdW-DF. This observation suggests a framework for an efficient implementation of quantum-physical modeling of the CNT bundling in more general nanotube bundles, including nanotube yarn and rope structures.

10 pages, 4 figures

References in corpus (3)

• Potassium intercalation in graphite: A van der Waals density-functional study
• Towards a working density-functional theory for polymers: First-principles determination of the polyethylene crystal structure
• Interaction energies of monosubstituted benzene dimers via nonlocal density functional theory

Cited by in corpus (9)

• van der Waals forces in density functional theory: The vdW-DF method
• Next-generation non-local van der Waals density functional
• van der Waals density functionals built upon the electron-gas tradition: Facing the challenge of competing interactions
• Rings sliding on a honeycomb network: Adsorption contours, interactions, and assembly of benzene on Cu(111)
• Interpretation of van der Waals density functionals
• Structure and binding in crystals of cage-like molecules: hexamine and platonic hydrocarbons
• Accurate non-empirical range-separated hybrid van der Waals density functional for complex molecular problems, solids, and surfaces
• Nanotube bundles and tube-tube orientation: A van der Waals Density Functional Study
• Density-functional theory of nonequilibrium tunneling