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Solitonic approach to the dimerization problem in correlated one-dimensional systems

J. Málek·S. -L. Drechsler·G. Paasch·K. Hallberg
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Abstract

Using exact diagonalizations we consider self-consistently the lattice distortions in odd Peierls-Hubbard and spin-Peierls periodic rings in the adiabatic harmonic approximation. From the tails of the inherent spin soliton the dimerization d_\infty of regular even rings is found by extrapolations to infinite ring lengths. Considering a wide region of electron-electron onsite interaction values U>0 compared with the band width 4t_0 at intermediately strong electron-phonon interaction g, known relationships obtained by other methods are reproduced and/or refined within one unified approach: such as the maximum of d_\infty at U \simeq 3 t_0 for g \simeq 0.5 and its shift to zero for g \to g_c \approx 0.7. The hyperbolic tangent shape of the spin soliton is retained for any U and g <~ 0.6. In the spin-Peierls limit the d_\infty are found to be in agreement with results of DMRG computations.

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J. Málek, S. -L. Drechsler, G. Paasch, K. Hallberg. 1997-08-29. Solitonic approach to the dimerization problem in correlated one-dimensional systems. https://doi.org/10.1103/physrevb.56.r8467

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