SU(4) Theory for Spin Systems with Orbital Degeneracy
arXiv:cond-mat/9804157 · doi:10.1103/PhysRevLett.81.3527
Abstract
The isotropic limit of spin systems with orbital degeneracy is shown to have global SU(4) symmetry. On many 2D lattices, the ground state does not posses long range order, which may explain the observed spin liquid properties of $LiNiO_2$. In the SU(4) Neel ordered state, spin-spin correlations can be antiferromagneitc between two neighboring sites with parallel magnetic moments.
11 pages, 2 figures. submitted to PRL