Correlation effects on the dynamics of bipolarons in nondegenerate conjugated polymers.

TLDR: This work uses a Su-Schrieffer-Heeger model modified to include electron-electron interactions via a Hubbard Hamiltonian, a Brazovskii-Kirova symmetry-breaking term, and an external electric field and shows that the velocity of the bipolaron increases first and then decreases with the increasing of the on-site Coulomb interaction.

Abstract: By employing an adaptive time-dependent density-matrix-renormalization-group method, we investigate the dynamics of a charged bipolaron in the presence of both electron-phonon and electron-electron interactions. We use a Su–Schrieffer–Heeger model modified to include electron-electron interactions via a Hubbard Hamiltonian, a Brazovskii–Kirova symmetry-breaking term, and an external electric field. Our results show that the velocity of the bipolaron increases first and then decreases with the increasing of the on-site Coulomb interaction, U. Furthermore, the dependence of the bipolaron velocity, bipolaron effective mass, and bipolaron stability on the lattice structures is discussed.