Extended states in disordered doped polyacetylene chains

In this work we study the electronic structure of ordered and disordered distributions of soliton-type defects along large, finite chains of trans-polyacetylene (trans-PA), as a function of the concentration of defects. The Negative Factor Counting method was used in a tight-binding parameterization with the geometrical data from Austin Method 1 calculations. Our results show the presence of extended (conducting) states at the Fermi level that could explain the semiconductor-metal transition for highly doped trans-polyacetylene, in accordance with the experimentally observed infrared-active vibrational states. © 1992.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP