Ferromagnetic topological crystalline insulating phase in the π-stacked graphene nanobelts under a small pressure

This work presents a topological material based on the graphene nanobelts. It is intrinsically magnetic. The band inversion in this system is partial and anomalous, as it was recently found in the Au-doped graphene and 2D molecular crystal. The metallic edge states with the Chern number equal to 1 exist in the ferro-and antiferromagnetic phase. The edge states become gapless at a small pressure, around 0.87 GPa, applied along the stacking axis. Their dispersions are not symmetric for the spin up and down. The graphene nanobelts are pi-stacked with the AB-type, and the zigzag edges are terminated with the O and H atoms at the opposite sides, in the reversed order along the stacking axis. The propagation of the topological edge states is parallel to the O center dot center dot center dot H-interaction direction, across the stacked belts.