Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 18: Electronic properties I
MM 18.3: Vortrag
Dienstag, 27. März 2007, 12:15–12:30, H6
Pressure effect on the electrical transport and structural properties of TiOCl — •Martin K. Forthaus1, Timo Taetz2, Angela Möller2, and Mohsen M. Abd-Elmeguid1 — 1II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln — 2Institut für Anorganische Chemie, Universität zu Köln, Greinstr. 6, 50939 Köln
We have investigated the effect of pressure on the electrical transport and structural properties of the quasi one dimensional Mott insulator TiOCl which exhibits an unconventional spin-Peierls transition at low temperatures. The analysis of the temperature dependence of the electrical resistivity as a function of pressure up to 22 GPa reveals that the energy gap Eg (at 300 K) decreases with increasing pressure with a sudden drop of about 40 % above 12 GPa. However, no metallic state is observed up to 22 GPa. The investigation of the pressure effect on the lattice parameters of TiOCl up to 8 GPa shows an extreme anisotropic decrease with increasing pressure, indicating a structural instability. These results are discussed in terms of a pressure-induced change of the electronic properties which is possibly driven by lattice instabilities under high pressure.