Effects of a transverse electric field on the electronic properties of single- and multi-wall BN nanotubes

In this work, we apply first-principles calculations, based on the density functional theory, to investigate the effect of a transverse electric field on the properties of single, double and triple-walled boron nitride nanotubes. The obtained results indicate that significant reduction on the formation and gap energies are observed for single-wall tubes with diameter greater than 10 angstrom. Such modifications arise from the Stark effect which is related to the polarization of the atomic orbitals. Nevertheless, for multi-walled tubes, a more selective mechanism takes place. Only the (5,0)@(13,0) double walled tube show significant gap narrowing. For the other structures it is speculated that the polarization associated to the internal tube compensate the polarization associated to the external one, neutralizing the effects of the applied electric field. (C) 2012 Elsevier Ltd. All rights reserved.