Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.42: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Screening of U in a three-band Hubbard model — •Clemens Adolphs and Erik Koch — German Research School for Simulation Sciences, FZ-Jülich and RWTH Aachen University, 52425 Jülich

We study the screening of the Hubbard interaction. As a concrete example, we consider a three-band Hubbard model with a central, half filled band, one filled band below, and an empty band above. We use the Lanczos algorithm to solve this model for small chains and calculate the spectral function. We then investigate a one-band Hubbard model where the renormalized interaction energy, U, for the one-band Hubbard model is calculated from the charging energy of the central orbital in the atomic limit of the original model. Comparing the spectral functions of the two models, we determine in which cases a one-band description using such a static renormalized U is feasible.