Berlin 2005 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Magnetismus
MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65
MA 20.119: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU C
Ferromagnetic Polarons in the 1D ferromagnetic Kondo Model with quantum mechanical S=3/2 corespins — •Danilo Neuber1, Maria Daghofer1, Hans Gerd Evertz1, Reinhard Noack2, and Wolfgang von der Linden1 — 1Inst. f. Theo. Physics,TU Graz, Petersg. 16, 8010 Graz, Austria — 2FB Physik, Philipps-Universität Marburg, 35032 Marburg, Germany
We present the first exhaustive numerical study of the ferromagnetic (FM) Kondo lattice model with quantum mechanical S=3/2 corespins. We treat non-degenerate orbitals in one dimension using the density matrix renormalization group (DMRG). We examine parameters relevant to manganites and the range of low to intermediate doping 0≥ x>0.5 and we include on-site Coulomb repulsion between the electrons.
In particular, we examine whether quantum fluctuations favor phase separation over the ferromagnetic polarons observed in a model with classical corespins. We find that quantum spins instead enhance the polaronic behavior and we find no phase separation for small doping. Coexistence of larger FM and antiferromagnetic (AFM) regions is only occasionally observed at rather high doping x≈0.3 near the transition to the FM ordered state.
We present a phase diagram with respect to doping and the t2g superexchange parameter J′ with and without Coulomb repulsion.