Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Correlated Electrons - Poster Session
TT 25.22: Poster
Mittwoch, 29. März 2006, 14:30–18:30, P1
Comparing the electronic structure of the quantum magnets TiOBr and TiOCl — •Michael Sing1, Markus Hoinkis1,2, Leonardo Pisani3, Roser Valenti3, Sander van Smaalen4, and Ralph Claessen1 — 1Experimentelle Physik 4, Universität Würzburg,D-97074 — 2Experimentalphysik II, Universität Augsburg, D-86135Augsburg, Germany — 3Institut für Theoretische Physik, UniversitätFrankfurt, D-60054 Frankfurt, Germany — 4Laboratory of Crystallography, University of Bayreuth,D-95440 Bayreuth, Germany
The layered Mott insulators TiOBr and TiOCl were recently interpreted as spin-Peierls compounds. They undergo two successive phase transitions with a non-magnetic spin-Peierls ground state and an intermediate state, in which an incommensurate order develops. In an extended temperature regime above the transitions the compounds display large fluctuation effects. It is still unclear how to interpret the electronic dispersions of TiOCl measured by photoelectron spectroscopy in the high temperature regime.[1] In order to elucidate the behavior of these compounds in the high temperature phase we studied the electronic structure of TiOBr and TiOCl by photoelectron spectroscopy and density-functional calculations. The experimentally and theoretically obtained density of states of both compounds are compared. Furthermore, we present momentum-resolved measurements and discuss the quasi-one-dimensional nature of the electronic dispersions. A detailed comparison of the two compounds makes the interpretation of the dispersions in a Mott-Hubbard picture appear less plausible.
[1] M. Hoinkis et al., Phys. Rev. B. 72, 125127 (2005)