Low-energy electronic states of carbon nanocones in an electric field

Abstract

The low-energy electronic states and energy gaps of carbon nanocones in an electric field are studied using a single-S-band tight-binding model. The analysis considers five perfect carbon nanocones with disclination angles of 60°, 120°, 180°, 240° and 300°, respectively. The numerical results reveal that the low-energy electronic states and energy gaps of a carbon nanocones are highly sensitive to its geometric shape (i.e. the disclination angle and height), and to the direction and magnitude of an electric field. The electric field causes a strong modulation of the state energies and energy gaps of the nanocones, changes their Fermi levels, and induces zero-gap transitions. The energy-gap modulation effect becomes particularly pronounced at higher strength of the applied electric field, and is strongly related to the geometric structure of the nanocone. Many theoretical [5][6][7][8][9][10] and experimental studies [11][12][13][14] of the geometric and electronic properties of carbon nanocones or nanotube tips have been revealed over the past decade. In general, the results have shown that the electronic structure, e.g. the electronic states, energy gaps and density of states, are highly sensitive to the symmetry of the edge sites at the open apex and to the curvature effect. However, relatively few studies have investigated the effect of an electric field on the electronic structures of carbon nanocones. It is known that an electric field can significantly affect the electronic properties of

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