Low-energy boron fullerenes: Role of disorder and potential synthesis pathways

We show by means of first-principles calculations that in boron nanostructures a large variety of two-dimensional structures can be obtained, all with similar energetic properties. Some of these new structures are more stable than both the B-80 fullerenes initially proposed by Szwacki et al. [Phys. Rev. Lett. 98, 166804 (2007)] and boron nanotubes. At variance from other systems like carbon, disordered configurations are energetically comparable with ordered ones. Cage-like structures that are not ordered are thus comparable in energy to the more ordered original B-80 fullerene. A comparison with other more disordered structures like bulk-like boron clusters is also presented. We found that in the presence of other seed structures (like Sc-3 or Sc3N), some endohedral cage-like structures are energetically preferred over bulk-like clusters. This result opens a new pathway for the synthesis of the B-80 fullerene as an endohedral fullerene as was done in the case of the C-80 fullerene.