A Hybrid Density Functional Study of Armchair Si and Ge Nanotubes

Prachi Pradhan; Asok Ray

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A Hybrid Density Functional Study of Armchair Si and Ge Nanotubes

Prachi Pradhan·Asok Ray

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Abstract

First principles calculations based on hybrid density functional theory have been used to study the electronic and geometric properties of armchair silicon and germanium nanotubes ranging from A (3, 3) through A (9, 9). The approach used is the finite cluster approach with hydrogen termination to simulate the effects of longer tubes. A detailed comparison of the structures and stabilities of Si and Ge nanotubes has been performed and the dependence of the HOMO- LUMO or band gaps on the tube diameters has been investigated. Silicon nanotubes appear to be less-puckered and more stable compared to germanium nanotubes. The largest silicon nanotube studied has a cohesive energy of 3.138eV/atom to be compared with the cohesive energy of 2.770eV/atom for the corresponding germanium nanotube. Contrary to some published results in the literature, silicon nanotubes do not appear to be metallic for the cases studied in the armchair configuration.

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Prachi Pradhan, Asok Ray. 2005-07-28. A Hybrid Density Functional Study of Armchair Si and Ge Nanotubes. https://arxiv.org/abs/physics/0507205

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