By means of ab initio calculations within the density functional theory, we have found that B80 fullerenes can condense to form stable face-centered-cubic fcc solids. It is shown that when forming a crystal, B80 cages are geometrically distorted, the Ih symmetry is lowered to Th, and four boron-boron chemical bonds are formed between every two nearest neighbor B80 cages. The cohesive energy of B80 fcc solid is 0.23 eV/atom with respect to the isolated B80 fullerene. The calculated electronic structure reveals that the fcc B80 solid is a metal. The predicted solid phase would constitute a form of pure boron and might have diverse implications. In addition, a simple electron counting rule is proposed, which could explain the stability of B80 fullerene and the recently predicted stable boron sheet.
@article{arxiv.0811.1282,
title = {Face-Centered-Cubic B$_{80}$ Metal: Density functional theory calculations},
author = {Qing-Bo Yan and Qing-Rong Zheng and Gang Su},
journal= {arXiv preprint arXiv:0811.1282},
year = {2009}
}