Novel three dimensional topological nodal line semimetallic carbon

A new cubic three dimensional carbon phase has been predicted by first-principles calculations. This phase is constructed by triangle graphene sheets, and dubbed as sc-C₉₆. The investigation on its electronic properties has indicated that sc-C₉₆ possesses a topological nodal line semimetal state, which protected by the combination of time reversal and spatial inversion symmetries, and negligible spin-orbit interaction. Due to the cubic symmetry, the Fermi surface of sc-C₉₆ is constituted of three nodal line circles. From the cohesive energy and phonon spectra, we find that sc-C₉₆ is dynamically stable and may be easily synthesized by polymerizing C₉₆ fullerene molecules at a relatively low pressure conditions (∼1 GPa).