Electronic properties of boron nitride nanocones under the influence of parallel and perpendicular external electric fields

Abstract

Boron-nitride nanocones with $60\ifmmode^\circ\else\textdegree\fi{}$, $120\ifmmode^\circ\else\textdegree\fi{}$, and $240\ifmmode^\circ\else\textdegree\fi{}$ disclination under the influence of parallel and perpendicular external electric fields are studied through first-principles calculations based on the density-functional theory. It is shown that the application of the external electric field ranging from 0 to $0.5\text{ }\text{V}/{\text{\AA{}}}^{\ensuremath{-}1}$, either parallel or perpendicular to the cones' axis, does not change significantly the formation energy of those systems. Changes at the densities of states according to the direction of the applied electric field are also analyzed showing that, except for the $240\ifmmode^\circ\else\textdegree\fi{}$ cone, the perpendicular field is more effective for gap reduction of those structures. A second-order Stark effect, more pronounced for the perpendicular direction, is observed when the energy shift is analyzed for the cones under the influence of the electric fields.