We present electron spin resonance data of Ti3+ (3d1) ions in single crystals of the novel layered quantum spin magnet TiOCl. The analysis of the g tensor yields direct evidence that the d_{xy} orbital from the t_{2g} set is predominantly occupied and owing to the occurrence of orbital order a linear spin chain forms along the crystallographic b axis. This result corroborates recent theoretical LDA+U calculations of the band structure. The temperature dependence of the parameters of the resonance signal suggests a strong coupling between spin and lattice degrees of freedom and gives evidence for a transition to a nonmagnetic ground state at 67 K.
@article{arxiv.cond-mat/0305317,
title = {Orbital order in the low-dimensional quantum spin system TiOCl probed by ESR},
author = {V. Kataev and J. Baier and A. Moeller and L. Jongen and G. Meyer and A. Freimuth},
journal= {arXiv preprint arXiv:cond-mat/0305317},
year = {2009}
}
Comments
revised version, accepted for publication in Phys. Rev. B, Rapid Comm