Electronic and lattice structures in potassium doped stage-1 polyacetylene

Effects of incommensurate arrangement of dopants to carbon atoms are investigated in K doped stage 1 polyacetylene ((CH) x). Owing to the large size of the valence orbitals of K, the interchain transfer (ICT) via dopants is not so much affected by dopants' arrangement. Interchain Coulomb (ICC) and dopants Coulomb (DC) potentials are evaluated by Davis's method. UHF calculations show that the ground state (g.s) is CDW bipolaron lattices ordered in phase on each chain, with the gap between the bipolaron band and the conduction band. Some other factor, such as the electron correlation, is essential to get a metallic (CH) x.