Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 13: Correlated Electrons: Low-dimensional Systems - Materials 1
TT 13.6: Vortrag
Dienstag, 26. Februar 2008, 10:45–11:00, H 2053
On the microscopic description of the spin-1/2 quantum magnet azurite — •Andreas Honecker1, Johannes Richter2, Helge Rosner3, Oleg Janson3, Roser Valenti4, Hem Kandpal4, Hena Das5, Bernd Wolf6, and Michael Lang6 — 1Institut für Theoretische Physik, Georg-August-Universität Göttingen — 2Institut für Theoretische Physik, Otto-von-Guericke Universität Magdeburg — 3Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden — 4Institut für Theoretische Physik, J.W. Goethe-Universität Frankfurt — 5S.N. Bose National Centre for Basic Sciences, Kolkata, India — 6Physikalisches Institut, J.W. Goethe-Universität Frankfurt
The mineral azurite Cu3(CO3)2(OH)2 exhibits interesting low-temperature properties like a magnetization plateau at 1/3 of saturation [H. Kikuchi et al., Phys. Rev. Lett. 94 (2005) 227201]. While the crystal structure suggests a description in terms of the spin-1/2 Heisenberg model on a distorted diamond chain, the values of the associated exchange constants have remained a matter of debate. Firstly, we present a study of the complete parameter space of the spin-1/2 Heisenberg model on the distorted diamond chain. Thermodynamic and dynamic properties are computed by exact diagonalization and compared to experimental results for azurite. In particular, we discuss the constraints obtained from recent inelastic neutron scattering results on the 1/3 plateau [K.C. Rule et al., arXiv:0709.2560]. Secondly, complementary ab-initio computations are performed in order to obtain further information about the relevant exchange paths in azurite as well as the values of the associated magnetic exchange constants.