Self-localized domain walls at π-conjugated branching junctions

Self-localized domain walls are found trapped at the potential wells created by pi-conjugated branching junctions due to the intrinsic electron-phonon couplings. The potential well depths are 0.14 eV for soliton, 0.28 eV for polaron, and 0.32 eV for exciton using the adapted Su-Schrieffer-Heeger model Hamiltonian, as compared to 0.23 eV for soliton, 0.25 eV for positively charged polaron, 0.33 eV for negatively charged polaron, and 0.21 eV for exciton using the ab initio Hartree-Fock method. Once the junction trapping wells are filled, however, branching junctions turn repulsive to additional self-localized domain walls. Torsions around the branching junction center have significant effects on the junction band gap and electron localizations. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665133]