Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 23: Low-Dimensional Systems: Other Materials
TT 23.3: Talk
Monday, March 31, 2014, 17:15–17:30, BEY 81
Hydrogen positions and their effect on exchange couplings of Cu-minerals — •Stefan Lebernegg1, Alexander Tsirlin2, Oleg Janson1,2, and Helge Rosner1 — 1MPI Chemical Physics of Solids, Dresden — 2National Institute of Chemical Physics and Biophysics, Tallinn
Exotic magnetic properties and the possibility of challenging our understanding of collective quantum phenomena are the reasons why low-dimensional spin-1/2 quantum magnets attract so much attention. Cu(2+) minerals belong to this class of compounds where several hundredths of them are provided by nature. However, only very few of them have ever been investigated with respect to their magnetic properties. Thus, the Cu-minerals keep a high potential for the discovery of new effects and materials. However, many of these compounds contain crystal water or OH groups where the position of hydrogen in the crystal structure crucially affects the magnetic behavior. Since the experimental determination of H-positions is highly elaborating if possible at all, these positions are usually not available in the structural data of minerals. We will, thus, present a valuable DFT-based alternative for determining the hydrogen positions. Then, the importance of the hydrogen positions for the magnetic properties and the computation of microscopic magnetic models will be discussed for selected Cu-minerals which have been investigated by combining several experimental and computational techniques.