Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 17: Symposium Quantum Magnetism in Molecule-based Materials

TT 17.2: Hauptvortrag

Montag, 7. März 2005, 10:50–11:25, TU H104

Design, Synthesis and Study of Model Quantum Magnets — •Andrew Harrison — School of Chemistry, The University of Edinburgh, Edinburgh, EH9 3JJ, UK

A major constraint on experimental studies of model magnets is the availability of suitable samples that provide tangible models to inspire or test theory. Some degree of rationalisation or even control may be introduced to synthetic strategies through consideration of bonding models: close–packing of spheres may be used to rationalise structures of ionic systems, while the linking of co–ordination polyhedra or vertices with a particular point group has some predictive power for systems where covalent bonding is prevalent. These strategies will be illustrated through the consideration of model frustrated systems such as triangular and kagome lattices, and specific examples will be given of model systems with S = 1/2 on such lattices, one of which shows evidence for a quantum ground state. We will also consider the possibility of tuning systems strongly through accessible magnetic fields and diamagnetic doping to access quantum phases. What is required here are low-spin, low-dimensional (and perhaps also frustrated) antiferromagnets with relatively weak magnetic exchange and diamagnetic analogues that either isostructural, or close to being so. Examples of copper salts that act as model S = 1/2 square Heisenberg antiferromagnets are presented