Hydrostatic pressure effects on the structural and electronicproperties of carbon nanotubes
We study the structural and electronic properties ofisolated single-wall carbon nanotubes (SWNTs) under hydrostatic pressureusing a combination of theoretical techniques: continuum elasticitymodels, classical molecular dynamics simulations, tight-bindingelectronic structure methods, and first-principles total energycalculations within the density-functional and pseudopotentialframeworks. For pressures below a certain critica pressure Pc, the SWNTs'structure remains cylindrical and the Kohn-Sham energy gaps ofsemiconducting SWNTs have either positive or negative pressurecoefficients depending on the value of (n,m) with a distinct "family" (ofthe same n-m) behavior. The diameter and chirality dependence of thepressure coefficients can be described by a simple analytical expression.At Pc, molecular-dynamics simulations predict that isolated SWNTs undergoa pressure-induced symmetry-breaking transformation from a cylindricalshape to a collapsed geometry. This transition is described by a simpleelastic model as arising from the competition between the bond-bendingand PV terms in the enthalpy. The good agreement between calculated andexperimental values of Pc provides a strong support to the "collapse"interpretation of the experimental transitions in bundles.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Basic EnergySciences
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 919746
- Report Number(s):
- LBNL-59688; PSSBBD; R&D Project: 403402; BnR: KC0301020; TRN: US0806475
- Journal Information:
- Physica Status Solidi (b), Vol. 241; Related Information: Journal Publication Date: 6 Oct 2004; ISSN 0370-1972
- Country of Publication:
- United States
- Language:
- English
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