International Workshop on Electronic Crystals
S. Brazovskii, P. Monceau and N. Kirova
J. Phys. IV France 131 (2005) 331-334
DOI: 10.1051/jp4:2005131083

Electronic structure and fluctuation effects in the spin-1/2 quantum magnet TiOCl

M. Sing¹, M. Hoinkis², J. Schäfer², M. Klemm², S. Horn², H. Benthien³, E. Jeckelmann⁴, L. Pisani⁵, R. Valentí⁵ and R. Claessen<sup>1

1</sup>  Experimentelle Physik 4, Universität Würzburg, 97074 Würzburg, Germany
²  Experimentalphysik II, Universität Augsburg, 86135 Augsburg, Germany
³  Fachbereich Physik, Philipps-Universität, 35032 Marburg, Germany
⁴  Institut für Theoretische Physik, Universität Hannover, 30167 Hannover, Germany
⁵  Institut für Theoretische Physik, Universität Frankfurt, 60054 Frankfurt, Germany

Abstract
We present a joint experimental and theoretical study of the spin-1/2 quantum magnet TiOCl. From polarization-dependent momentum-resolved photoemission spectroscopy we can exclude sizable phonon-induced orbital fluctuations as origin for the non-canonical phenomenology of the spin-Peierls transition in this compound. While our data does confirm the quasi-one-dimensional character of the electronic structure along the crystallographic b-axis as inferred from previous LDA+U calculations these as well as other band and model calculations apparently fail to describe the detailed behavior of the quasi-one-dimensional dispersions in the normal state of this material.

© EDP Sciences 2005