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arXiv · 0704.1168

Electronic Properties of Carbon Nanotubes Calculated from Density Functional Theory and the Empirical pi-Bond Model

Deep Shah·Nicolas A. Bruque·Khairul Alam·Roger K. Lake·Rajeev R. Pandey
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Abstract

The validity of the DFT models implemented by FIREBALL for CNT electronic device modeling is assessed. The effective masses, band gaps, and transmission coefficients of semi-conducting, zigzag, (n,0) carbon nanotubes (CNTs) resulting from the ab initio tight-binding density functional theory (DFT) code FIREBALL and the empirical, nearest-neighbor pi-bond model are compared for all semiconducting n values 5 <(=) n <(=) 35. The DFT values for the effective masses differ from the pi-bond values by +(-) 9% over the range of n values, 17 <(=) n <(=) 29, most important for electronic device applications. Over the range 13 <(=) n <(=) 35, the DFT bandgaps are less than the empirical bandgaps by 20-180 meV depending on the functional and the n value. The pi-bond model gives results that differ signifcantly from the DFT results when the CNT diameter goes below 1 nm due to the large curvature of the CNT. The pi-bond model quickly becomes inaccurate away from the bandedges for a (10, 0) CNT, and it is completely inaccurate for n <(=) 8.

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Deep Shah, Nicolas A. Bruque, Khairul Alam, Roger K. Lake, Rajeev R. Pandey. 2007-04-09. Electronic Properties of Carbon Nanotubes Calculated from Density Functional Theory and the Empirical pi-Bond Model. https://arxiv.org/abs/0704.1168

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