Regensburg 2000 – scientific programme
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TT: Tiefe Temperaturen
TT 21: Korrelierte Elektronen II
TT 21.5: Talk
Thursday, March 30, 2000, 15:45–16:00, H18
Optical conductivity of strongly correlated electrons — •Eric Jeckelmann1, Florian Gebhard1, and Fabian H.L. Essler2 — 1Fachbereich Physik, Philipps-Universität Marburg — 2Department of Physics, King’s College London
We employ the density-matrix renormalization group with the correction vector method to determine the optical conductivity of the one-dimensional half-filled extended Hubbard model on lattices with up to 128 sites. Comparison with exact results (non-interacting electrons, field-theory approach, and strong-coupling expansions) shows that this method is very accurate over the entire absorption spectrum. We have found that the optical conductivity of a one-dimensional Mott-Hubbard insulator vanishes continuously at the absorption threshold, in contrast to the divergence observed in a one-dimensional band (Peierls) insulator. Combining both lattice and correlation effects, we investigate the optical properties of Mott-Peierls insulators from the limit of strong electronic correlations to the limit of dominant lattice effects. In particular, we study the formation of excitons below the absorption edge due to the non-local parts of the electron-electron interaction.