Figure 1

Electronic structure of a clean SWNT with and without a transverse electric field ($E_{\mathrm{ext}}$). The Fermi level is set to zero in all figures. (a) Band structure near the Fermi level of a clean $(10,10)$ SWNT with $E_{\mathrm{ext}}=0$. The inset is the atomic structure of the $(10,10)$ SWNT. (b) Band structure of a clean $(10,10)$ SWNT with $E_{\mathrm{ext}}=0.4\mathrm{V}/\AA$. The inset shows the nanotube and the applied electric field perpendicular to the tubular axis.Reuse & Permissions

Figure 2

Electrical resistances of single-impurity-doped SWNTs in transverse electric field $E_{\mathrm{ext}}$. (a) A ball-and-stick model of a nitrogen- or boron-doped SWNT in a transverse electric field. The impurity is denoted by a darker atom. The direction of the arrows (from the impurity-doped side to the other) corresponds to $E_{\mathrm{ext}}>0$. (b) Calculated two-probe electrical resistances ($R$) of a nitrogen-doped $(10,10)$ SWNT, a boron-doped one, and a clean one. Transmission spectra $T(E)$ of (c) a nitrogen-doped and (d) a boron-doped $(10,10)$ SWNT in various transverse electric fields.Reuse & Permissions

Figure 3

Electrical resistance of nitrogen and boron codoped SWNTs in transverse electric field $E_{\mathrm{ext}}$. (a) A schematic diagram of a nitrogen (blue or dark grey dot) and boron (red or grey dot) codoped SWNT in a transverse electric field. The direction of the arrows corresponds to $E_{\mathrm{ext}}>0$. (b) Calculated two-probe electrical resistances ($R$) of nitrogen and boron codoped ($n,n$) SWNTs ($n=10,20,30$). Open and solid circles are results from ab initio calculations for $(10,10)$ and $(20,20)$ SWNTs, respectively, and lines are results from tight-binding approximations. (c) Transmission spectra $T(E)$ of the nitrogen and boron codoped $(10,10)$ SWNT in electric fields of 0.0 and $0.4\mathrm{V}/\AA$. (d) Color-scale plot of transmission spectra $T(E)$ as a function of energy $E$ and electric field $E_{\mathrm{ext}}$ for the nitrogen and boron codoped $(10,10)$ SWNT. The color-scale bar is placed on top of the plot.Reuse & Permissions

Figure 4

(a) Calculated two-probe resistance of a $(10,10)$ SWNT with a vacancy in transverse electric fields ($E_{\mathrm{ext}}$). Solid circles result from ab initio calculations, while the solid line is from a tight-binding approximation. The direction of the electric field in the inset represents $E_{\mathrm{ext}}>0$. (b) Transmission spectra [$T(E)$] of the $(10,10)$ SWNT with the vacancy as a function of energy ($E$). From the top to the bottom panel, the applied fields are $+0.3$, 0.0, and $-0.3\mathrm{V}/\AA$, respectively.Reuse & Permissions