Correlation Effects on the Spin Soliton in Polyacetylene

抄録

Effects of electron correlations are studied in trans-polyacetylene up to the second order with respect to the fluctuations around the Hartree-Fock solution. We present results for a spin soliton, which has a negative spin density due to correlations. It is found that the second-order corrections suppress the dependences of the creation energy, the position of the midgap level and the spin density profile on correlations in the Hartree-Fock approximation, and that the suppression is large when the spin density alternation around the soliton is large. Comparing the present results with recent ENDOR experiments, we find that the observed spin density profile can be reproduced if we take the dimensionless electron-lattice coupling strength λ=0.1, the onsite Coulomb energy U=1.6t₀ and the nearest-neighbor interaction V=0.8t₀, with t₀ as the nearest-neighbor hopping integral.