Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 79: Correlated Electrons - Poster Session
TT 79.43: Poster
Mittwoch, 2. April 2014, 15:00–19:00, P2
Magnetic properties of antiferromagnetic Heisenberg chains with spin-S boundary defects in magnetic fields — •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 anisotropic S=1/2 Heisenberg chains with spin-S boundary defects with an impurity coupling beyond simple superexchange. We employ finite temperature Quantum Monte-Carlo methods based on Stochastic Series Expansion. For particular choices of parameters and at zero temperature the models we investigate are exactly solvable by means of Bethe Ansatz techniques. Results will be presented for magnetic properties as functions of uniform and edge magnetic fields, exchange-coupling constants, anisotropy, temperature, and system size. Properties include the susceptiblity and magnetization. Of special interest are bulk and boundary properties which are expressed in orders of 1/L and the magnetization with respect to the corresponding magnetic fields. We will compare our findings from both methods in the zero temperature limit.