Supercarbon assembly inspired two-dimensional hourglass fermion

By using a tight-binding model, first-principles calculations, and ab initio molecular dynamics simulations, we theoretically demonstrate that the C76-Td-assembled two-dimensional (2D) honeycomb lattice is stable at room temperature and is resistant to mechanical deformation. We disclose that each C76-Td mimics a single carbon atom (geometrically and electronically); hence, it plays the role of one supercarbon. This inspires that the 2D material exhibits an exotic hourglass-like fermion at the Fermi level. Furthermore, we suggest that biaxial strains could modify the hourglass shape, including the electronic Fermi velocity, and induce magnetization. Hexagonal boron nitride can be employed as a protective layer without affecting the electronic structure of this material. This hourglass fermion has the potential to serve as a promising material for high-speed electronic devices and to bridge the gap between zero-dimensional spherical carbon clusters and two-dimensional graphene.