Exact Ground States in Spin Systems with Orbital Degeneracy

Abstract

We present exact ground states in spin models with orbital generacy in one and higher dimensions. A method to obtain the exact ground states of the models when the Hamiltonians are composed of the products of two commutable operators is proposed. For the case of the spin-1/2 model with two-fold degeneracy some exact ground states are given, such as the Valence-Bond (VB), the magnetically ordered, and the orbitally ordered states under particular parameter regimes. We also find the models with the higher spin and degeneracy which have the new types of VB ground states in the spin and the orbital sectors.

4 pages(JPSJ.sty), 2 figures(EPS), to appear in J. Phys. Soc. Jpn. 68, No.2 (1999) 322

References in corpus (3)

• Quantum Melting of Magnetic Order due to Orbital Fluctuations
• Non-Haldane Spin Liquid Models with Exact Ground States
• Valence-bond states in dynamical Jahn-Teller molecular systems

Cited by in corpus (10)

• Scalar chiral ground states of spin ladders with four-spin exchanges
• Spin-Orbital Entanglement and Phase Diagram of Spin-orbital Chain with $SU(2)\times SU(2)$ Symmetry
• Elementary excitations in one-dimensional spin-orbital models: neutral and charged solitons and their bound states
• Exact spin-orbital separation in a solvable model in one dimension
• Exact Bond-Located Spin Ground State in the Hubbard Chain with Off-Diagonal Coulomb Interactions
• Role of Bond-Bond Interaction in the Extended Hubbard Chain
• Spin and orbital valence bond solids in a one-dimensional spin-orbital system: Schwinger boson mean field theory
• Exact Electron-Pairing Ground States of Tight-Binding Models with Local Attractive Interactions
• Exact Plaquette-Ordered Ground States in the Generalized Hubbard Model in Arbitrary Dimensions
• Exact Ground States of the Extended Hubbard Model on the Kagome lattice