Anatase(001) 3 ML Nanotubes, The First TiO2 Nanotube With Negative Strain Energies: A DFT Prediction

Nanotubes created from a three monolayer thick anatase(001) layer were investigated by DFT calculations in the 33-66 angstrom diameter range. Strain energies were found to be negative in the whole diameter range, indicating the stability of the nanotubes relative to the flat layer, providing a possible explanation for the rolling-up of the nanotubes. The strain energy curve was shown to exhibit a minimum close to the experimentally observed TiO2 nanotube diameters. Band gaps of the nanotubes were found to be close to that of the flat layer and more than 1 eV with respect to bulk anatase.