Pore symmetry dependence of band gap of nanoscale periodic porous graphites with differenet pore shapes

The electronic energy states of nanoscale periodic porous graphites with different shape,, of pores with acene and phenanthrene edge structures are theoretically studied using the two-dimensional (M) tight-binding crystal orbital method in the framework of the Huckel approximation. The behaviors of the band gaps of the periodic porous graphite depend markedly not on the shape of pores but on the symmetry of the pore,,, and some of them for the periodic porous graphite with symmetric pores have the exact periodicity as a function of the separation between neighboring pores. Moreover, it has been originally thought that the separation of charge and spin in two dimensions (2D) cannot appear without transition metals however. the appearance of the separation of charge and spin has been theoretically demonstrated in nanoscale periodic porous graphite with an odd number of atoms in the unit cell.