Theoretical study of α- and γ-V2O5 double-walled nanotubes

The first-principles calculations of the atomic and electronic structure of double-walled nanotubes (DWNTs) of γ-V2O5 have been performed and the obtained properties have been compared with those of α-V2O5 ones. The DWNT structure relaxation leads to the formation of two types of local regions: (1) adhesion regions and (2) puckering regions. Although the structure of adhesion regions of α-V2O5 DWNTs is close to the structure of bulk α-V2O5, this is not the case for γ-V2O5 DWNTs. The resulting structure of adhesion regions in γ-V2O5 SWNTs allows us to assume the existence of hypothetical stable phases, with one of them resembling the experimentally observed R-Nb2O5 and (V0.7Mo0.3)2O5 crystals.