Structure and energy spectra of a two-dimensional dielectric carbon allotrope

The energy spectra of two classes of infinite polymers consisting of an alternating fusion of cyclobutadiene and benzene rings are investigated theoretically. The dependence of the band gap on the topology, geometry and electron correlation is examined. By increasing the number of the cyclobutadiene and benzene rings in the elementary units the polymers tend towards a two dimensional carbon allotrope C. In contrast to graphite, the two-dimensional net C is a dielectric with a band gap ΔE ≈ 2 eV.