Dimension reduction due to the orbital ordering has recently been proposed to explain the exotic charge, magnetic and structural transitions in some three-dimensional (3D) transitional metal oxides. We present optical measurement on a spinel compound MgTi2O4 which undergoes a sharp metal-insulator transition at 240 K, and show that the spectral change across the transition can be well understood from the proposed picture of 1D Peierls transition driven by the ordering of dyz and dzx orbitals. We further elaborate that the orbital-driven instability picture applies also very well to the optical data of another spinel CuIr2S4 reported earlier.
@article{arxiv.cond-mat/0607813,
title = {Optical study of MgTi$_2$O$_4$: Evidence for an orbital-Peierls state},
author = {J. Zhou and G. Li and J. L. Luo and Y. C. Ma and Dan Wu and B. P. Zhu and Z. Tang and J. Shi and N. L. Wang},
journal= {arXiv preprint arXiv:cond-mat/0607813},
year = {2009}
}
Comments
5 pages, 6 figures, to be published in Phys. Rev. B