Bonding Frustration in the 9.5 GPa fcc Polymeric C₆₀

Abstract

We argue that the face‐centered cubic (fcc) polymeric C 60 phase obtained at 9.5 GPa can be mapped onto the classical frustrated Ising fcc antiferromagnet. Extensive density functional theory (DFT) calculations show that at 9.5 GPa 56/65 2+2 cycloaddition polymeric bonds are formed between neighboring molecules having different standard orientations but do not form when they have the same standard orientation. These “antiferromagnetic” bonds cannot be fully satisfied in the fcc lattice of the polymeric phase, resulting in a frustrated structure. By analyzing the ground state configurations of the frustrated Ising fcc antiferromagnet, a picture of the polymeric frustrated structure was obtained.