Ab initio Study of Clusters and Nanotubes in Electric Fields
We have investigated the reactions of silicon-carbon mixed clusters, Si2C3 and Si3C2 and various carbon nanotubes to the applied electric fields by first-principles supercell calculations using the local density approximations and the pseudopotential plane wave method. We manipulated the mixed clusters theoretically with a high electric field. Linear (Si2C3) and plane (Si3C2) clusters bend in the direction of the field. The field-induced distortion is interpreted using the electronegativity of Si and C atoms. The local field enhancement at the tips of carbon nanotubes and the screening of the electric field inside the nanotubes are considerable for nanotubes with a small gap between the highest occupied band (HOB) and the lowest unoccupied band (LUB) in the electronic states. The result also suggests an important role of the localized states of conducting nanotubes with small electronic gaps in field emissions.
KeywordsCarbon Nanotubes Electric Dipole External Electric Field Applied Electric Field Local Density Approximation
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