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TT: Tiefe Temperaturen
TT 32: Theoretische Modelierung von Materialien mit korrelierten Elektronen
TT 32.3: Talk
Friday, March 12, 2004, 10:45–11:00, H18
TiOCl, an orbital-ordered system? — •Roser Valenti1, T. Saha-Dasgupta2, Helge Rosner3, and Claudius Gros4 — 1Institut für Theoretische Physik, Universität Frankfurt, D-60054 Frankfurt — 2S.N. Bose National Centre for Basic Sciences, Kolkata 700098, India — 3Max-Planck Institute for Chemical Physics of Solids, D-01187 Dresden — 4Theoretische Physik, Universität des Saarlandes, D-66041 Saarbrücken
We present first principles density functional calculations and downfolding studies of the electronic and magnetic properties of the layered quantum spin system TiOCl. We attempt to clarify the concept of orbital ordering in this material and discuss existing studies. An analysis of the electronic structure of slightly distorted structures according to the phononic modes allowed in this material suggests that this system is subject to large orbital fluctuations driven by the electron-phonon coupling. Based on these results, we propose a microscopic explanation of the behavior of TiOCl at lower temperatures.