Structure and properties of diamond-like carbon nanotubes

An ab initio study of the structure and properties of diamond-like carbon nanotubes formed during the rolling of the L${}_{4}$ diamond-like layer has been performed. As a result of calculations by the density functional theory method, it is established that only diamond-like nanotubes ($n$,0)${}_{{\rm L}_4}$ having a polyprismatic shape can stably exist. The point symmetry group of these nanotubes is $n/mmm$. The value of the translation parameter is in the range from 1.6224 to 1.6342 Å. Molecular dynamics calculations have shown that a nanotube (5,0)${}_{{\rm L}_4}$, which has a minimum total energy, should be stable up to 150 K. The isolated nanotube (5,0)${}_{{\rm L}_4}$ has a high Young's modulus (890 GPa) and a band gap of 0.6 eV, which is typical for a semiconductor. Materials based on the diamond-like carbon nanotube (5,0)${}_{{\rm L}_4}$ densely packed bundles can be experimentally identified using a calculated powder X-ray diffraction pattern.