Geometric and electronic structures of a two-dimensional covalent network of sp2 and sp3 carbon atoms

Abstract

Based on first-principles total-energy calculations, we investigated the geometric, electronic, and spin structures of two-dimensional honeycomb networks of polymerized C40. Our calculations showed that the polymerized C40 possesses two polymeric structures that are statically and dynamically stable, retaining their covalent topologies up to 3000K. The C40 polymers are semiconductors with a tiny band gap and small dispersion bands near the gap, which causes the magnetic ordering of both ferromagnetic and antiferromagnetic states as their stable states. In addition to spin polarization, the C40 polymer possesses the electronic polarity normal to the two-dimensional covalent network because of the inhomogeneous charge density arising from the arrangement of pentagonal and hexagonal rings in the networks.