The electronic band structure of polydiacetylenes with second- and third-neighbor hopping interaction

Abstract

We have studied the energy band structure of polydiacetylenes (PDAs) using the extensional Hückel Hamiltonian that includes the nonnearest-neighbor hopping interactions. The results show that with increase in the nonnearest-neighbor hopping interaction parameters ρ1 and ρ2, (i) the energy band symmetry is broken and the energy gap 2Δ has changed, (ii) the locations and the widths of energy bands have changed and their shifts depend mainly on ρ1 (next-neighbor hopping interactions), and (iii) the energy gap 2Δ depends mainly on ρ2 (third-neighbor hopping interactions), the effects of the nonnearest-neighbor hopping interaction on the band structure are discussed. PACS No.: 31.15Ct