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TT: Tiefe Temperaturen

TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique

TT 16.32: Poster

Samstag, 5. März 2005, 11:00–16:30, Poster TU C

Exact diagonalization studies of hole-doped spin rings — •Fatiha Ouchni and Jürgen Schnack — Universität Osnabrück, Fachbereich Physik, D-49069 Osnabrück, Germany

Motivated by the effect of holes on the electric and magnetic properties of the spin-chain and -ladder compound Sr₁₄Cu₂₄O₄₁, we study the influence of the Coulomb repulsion between different holes on the ring using exact diagonalization of an extended Hubbard model via a Lanczos procedure. The resulting correlation functions depend strongly on the strength and the range of the screened Coulomb potential. It is shown that strong Coulomb repulsion leads to well-localized holes and very likely to a dimerized ground state in the case of 60 % intrinsic hole doping.