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TT: Fachverband Tiefe Temperaturen

TT 3: Correlated Electrons: Low-Dimensional Systems - Models 1

TT 3.6: Vortrag

Montag, 11. März 2013, 10:45–11:00, H9

DMRG study of the optical conductivity of the 1D Hubbard model — •Alexander C. Tiegel, Piet E. Dargel, and Thomas Pruschke — Institut für Theoretische Physik, Georg-August-Universität Göttingen, Germany

The zero-temperature optical conductivity of the Hubbard model in one dimension is studied for various values of the on-site repulsion U and the electronic filling n by means of frequency-resolved density-matrix renormalization group (DMRG) methods. The focus of this work is the determination of the optical gap E_opt and the investigation of the leading frequency dependence at the onset of the finite-frequency conductivity. At half-filling, our data is compatible with a square-root increase above the band threshold, which is in agreement with conformal field theory and DDMRG results in the literature. Away from half-filling, we find an increasing pseudogap E_opt with the amount of doping. These results as well as the extracted exponents at the onset for n<1 are directly compared to existing field-theoretical values.