文摘
The electronic properties of exohedrally doped double-walled carbon nanotubes (DWNTs) have been investigated using density functionaltheory and resonance Raman spectroscopy (RRS) measurements. First-principles calculations elucidate the effects of exohedral doping onthe M@S and S@M systems, where a metallic (M) tube is either inside or outside a semiconducting (S) one. The results demonstrate thatmetallic nanotubes are extremely sensitive to doping even when they are inner tubes, in sharp contrast to semiconducting nanotubes, whichare not affected by doping when the outer shell is a metallic nanotube (screening effects). The theoretical predictions are in agreement withRRS data on Br2- and H2SO4-doped DWNTs. These results pave the way to novel nanoscale electronics via exohedral doping.