We present a band structure study of orbital polarization and ordering in the two-dimensional triangular lattice transition metal compounds LiVO_2 and NaTiO_2. It is found that while in NaTiO_2 the degeneracy of t_{2g} orbitals is lifted due to the trigonal symmetry of the crystal and the strong on cite Coulomb interaction, in LiVO_2 orbital degeneracy remains and orbital ordering corresponding to the trimerization of the two-dimensional lattice develops.
@article{arxiv.cond-mat/9712230,
title = {Orbital polarization in LiVO_2 and NaTiO_2},
author = {S. Yu. Ezhov and V. I. Anisimov and H. F. Pen and D. I. Khomskii and G. A. Sawatzky},
journal= {arXiv preprint arXiv:cond-mat/9712230},
year = {2009}
}