Optimized geometry and electronic structure of three-dimensional β-graphyne

摘要

β-graphyne, a carbon allotrope, is a gapless semiconductor with hexagonal lattice symmetry, just like graphene. We calculated the optimized structure and electronic structures of some possible three-dimensional β-graphyne stacking arrangements by means of the first-principles frozen-core projector augmented-wave method implemented in the Vienna ab initio simulation package. The optimized lattice constant a of the three-dimensional β-graphyne turns out to be 9.46 ?, which is slightly smaller than its two-dimensional counterpart. The binding energy is about 90% of that of graphite, which suggests that three-dimensional β-graphyne will be stable when it is synthesized. The band structure is calculated via the hybrid functional. We found that the most stable threedimensional stacking arrangement is an indirect band gap semiconductor with an energy gap of 0.1 eV.