The study of the properties of nanostructures in an electric field is very important not only from the fundamental point of view but also for practical applications. According to classical physics, an insulating system will be broken down in a large electric field. Can we predict such a behaviour for nanostructures using ab initio calculation? Such an attempt is made in this paper. The electronic structure and charge distributions of the thinnest (SiO2)n wire in electric field are studied in detail with a first-principles method. It is found that the HOMO-LUMO gap increases with size and saturates at large values of 6.4 eV when n ≥ 12, suggesting that the SiO2 chain can be a very good insulating nanowire. However, when the wire is in an applied electric field, the HOMO and LUMO energies of the wire decrease linearly at different speeds, and the gap approaches zero, at which point the insulating wire is broken down by the electric field.
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering