Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.67: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Thermodynamic properties of spin-S boundary defects in antiferromagnetic Heisenberg chains — •Björn Willenberg1,3, Jan Grelik2,3, Wolfram Brenig1,3, and Holger Frahm2,3 — 1Institute for Theoretical Physics, Technische Universität Braunschweig — 2Institute for Theoretical Physics, Leibniz Universität Hannover — 3Niedersächsische Technische Hochschule, NTH
We investigate magnetic spin-S impurities in contact to isotropic and anisotropic S=1/2 Heisenberg chains with open boundary conditions and an impurity coupling beyond simple superexchange. We employ finite temperature Quantum Monte-Carlo methods based on Stochastic Series Expansion. Results will be presented for thermodynamic properties as functions of temperature, exchange-coupling constants, anisotropy, magnetic fields, and system size. For particular choices of parameters the models we investigate are exactly solvable by means of Bethe Ansatz techniques which will be used to obtain quantities like energy, magnetization, and susceptibility at zero temperature. In this limit we will compare our findings from both methods.