Electronic and lattice structures in potassium-doped stage-1 polyacetylene

Abstract

Interchain transfers (ICTs) via dopants and interchain Coulomb (ICC) and dopant Coulomb (DC) potentials in a Thomas-Fermi approximation are calculated in a stoichiometrically K-doped stage-1 polyacetylene ((CH) x ). Owing to the large sizes of the valence orbitals of K, dopants give the most important and dense net of ICTs. We make Hartree-Fock calculations to see their effects using a reasonable intrachain Hamiltonian. ICTs slightly affect the intrachain states but greatly change the orbital energy spectrum though there is only a small effect near the Fermi energy. The DC converts the BOW charged soliton lattice into a CDW bipolaron lattice. The ICC enlarges the gap and makes the phases of the bipolaron lattices ordered. Highly K-doped (CH) x has a gap and lattice distortions similar to those of charge soliton lattices. Electron correlation is essential to achieve metallic (CH) x .