Correlation effects on the dynamics of bipolarons in nondegenerate conjugated polymers

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.

Effect of Electron−Electron Interactions on the Charge Carrier Transitions intrans-Polyacetylene

“…[36][37][38][39] All our numerical results presented in this work are well-converged values calculated with ǫ ρ = 1.0 × 10 −7 and ∆t=0.05 fs.…”

“…Recent works have carefully studied the accuracy performance of the combined TD-DMRG/MD method and verified its reliability with suitable adopted parameters and it was found that one can achieve reliable and converged numerical results if the DMRG truncation weight ǫ ρ is taken small enough (ǫ ρ ≤ 1.0 × 10 −6 ) and suitable time step ∆t values around 0.01∼0.05 fs are chosen. [36][37][38][39] All our numerical results presented in this work are well-converged values calculated with ǫ ρ = 1.0 × 10 −7 and ∆t=0.05 fs.…”

“…The main idea of this method is to evolve the π-electron part by the adaptive TDDMRG and move the backbone part by classical MD iteratively and nonadiabatically to include nearly all relevant electron-phonon and electron-electron interactions. Details about such the combined TDDMRG/MD method can be found in the recent papers [36][37][38][39].…”

Spin-flip processes of polarons by magnetic impurities in conjugated polymers

“…Previous works on the dynamics of solitons/ polarons/bipolarons in conjugated polymers show that the t-DMRG method is an efficient approach to perform a realtime dynamics of many-body systems including both electron-electron and electron-phonon interactions. [25][26][27][28] In this paper, we present quasiexact numerical results of the real-time dynamics of the Hamiltonian Eq. ͑1͒ for realistic sizes of up to N = 128 sites.…”

“…There have been extensive researches about the polaron dynamics in organic polymers. [19][20][21][22][23][24][25][26][27][28] However, these studies did not take into account the spin degree of freedom of polarons. In an earlier paper, the spin-flip process of polarons in a polymer chain with a single-site classical magnetic impurity was discussed by one of the authors and his co-workers.…”