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Physical Review B

Exact ground states for spin-1 systems with spin-orbital coupling

Shu Chen, Yupeng Wang

Published Nov 4, 2005• 1 citation
Publisher

Abstract

We present rigorous results on the ground states of spin-1 models with orbital degeneracy. The ground states are constructed by utilizing the approach of projection operators. Possible generalization to two-dimensional systems and higher spin systems is also discussed.
DOI
10.1103/physrevb.72.172404

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A spin-12\frac{1}{2}21​ system with double orbital degeneracy may possess SU(4) symmetry. According to the group theory a global SU(4) singlet state can be expressed as a linear combination of all possible configurations consisting of four-site SU(4) singlets. Following Andersion's idea for spin-12\frac{1}{2}21​ system, we propose that the ground state for the antiferromagnetic SU(4) model is an SU(4)-resonating valence-bond (RVB) state. A short-range SU(4)-RVB state is a spin and orbital liquid, and its elementary excitations has an energy gap. We construct a series of solvable models that ground states are short-range SU(4)-RVB states. The results are generalized to the antiferromagnetic SU(N) models.
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