A 2D quantum antiferromagnet with a four-fold degenerate valence-bond-solid ground state

Abstract

We study the competition between antiferromagnetic order and valence bond solid formation in a two-dimensional frustrated spin-1/2 model. The J1-J2 model on the square lattice is further frustrated by introducing products of three-spin projectors which stabilize four dimer-product states as degenerate ground states. These four states are reminiscent of the dimerized singlet ground state of the Shastry-Sutherland model. Using exact diagonalizations, we study the evolution of the ground state by varying theratio of interactions. For a large range of parameters (J2 > 0.25J1), our model shows a direct transition between the valence-bond-solid phase and the collinear antiferromagnetic phase. For small values of J2, several intermediate phases appear which are also analyzed.

References in corpus (7)

• "Deconfined" quantum critical points
• Quantum criticality beyond the Landau-Ginzburg-Wilson paradigm
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• Plaquette valence bond solid in the frustrated Heisenberg quantum antiferromagnet on the square lattice
• The J1-J2 model: First order phase transition versus deconfinement of spinons
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Cited by in corpus (12)

• Ground-state phases of the spin-1/2 J_1-J_2 Heisenberg antiferromagnet on the square lattice: A high-order coupled cluster treatment
• Plaquette valence-bond ordering in J_1-J_2 Heisenberg antiferromagnet on the honeycomb lattice
• Quantum phase transitions in the exactly solved spin-1/2 Heisenberg-Ising ladder
• Fourfold degenerate columnar-dimer ground state in square lattice antiferromagnets
• Honeycomb antiferromagnet with a triply degenerate dimer ground state
• Dual dynamic scaling in deconfined quantum criticality
• Translation-Invariant Parent Hamiltonians of Valence Bond Crystals
• Triplon mean-field analysis of an antiferromagnet with degenerate Shastry-Sutherland ground states
• Exact staggered dimer ground state and its stability in a two-dimensional magnet
• Quantum to classical transition in the ground state of a spin-$S$ quantum antiferromagnet
• Exact plaquette singlet phases in an orthogonal-plaquette model
• Haldane's Instanton in 2D Heisenberg model revisited: along the Avenue of Topology