Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Correlated Electrons: Spin Systems and Itinerant Magnets 2
TT 30.3: Vortrag
Donnerstag, 28. Februar 2008, 11:00–11:15, EB 202
Heisenberg Spin-1 Chains and Ladders with Bilinear-Biquadratic Interactions in a Magnetic Field — •Salvatore R. Manmana1, Tamás A. Toth1, Andreas Läuchli2, and Frédéric Mila1 — 1Institute of Theoretical Physics (CTMC), EPF Lausanne, CH-1015 Lausanne, Switzerland — 2IRRMA, PPH-Ecublens, CH-1015 Lausanne, Switzerland
We investigate the magnetic properties of Heisenberg spin-1 chain and ladder systems with bilinear-biquadratic interactions in a magnetic field by applying the density matrix renormalization group method (DMRG) and a variational wavefunction ansatz. For the chains, the magnetization and the dominating spin and quadrupolar correlation functions are computed in the various regions of the zero-field phase diagram. In the critical quadrupolar phase (π/4 < θ < π/2), the magnetization curve is dominated by a pronounced kink at finite values of the field and the magnetization. After giving a sketch of the zero-field phase diagram of the ladder systems, we present results for various sets of parameters, aiming to gain insight into magnetization properties in the presence of frustration.