Fourfold degenerate columnar-dimer ground state in square lattice antiferromagnets

Abstract

We construct and study two frustrated quantum spin-1/2 models on square lattice, which are like the antiferromagnetic $J_1$-$J_2$ model with some additional four-spin exchange interactions. These models admit an exactly solvable case in which the ground state consists of four degenerate columnar-dimer singlet (CDS) configurations. Away from the exact case, we employ bond-operator mean-field theory to investigate the evolution of the ground state by varying the interaction parameters. The mean-field calculation reveals a quantum phase diagram in which the CDS phase undergoes a continuous phase transition to either Néel or collinear ordered antiferromagnetic phases.

revtex4, 16 eps files; total 10 pages; accepted for publication in Phys. Rev. B

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Cited by in corpus (10)

• Ground-state phases of the spin-1/2 J_1-J_2 Heisenberg antiferromagnet on the square lattice: A high-order coupled cluster treatment
• Bond-operators and triplon analysis for spin-S dimer antiferromagnets
• The Phase Transition of Square Lattice Antiferromagnets at Finite Temperature
• Plaquette-triplon analysis of magnetic disorder and order in a trimerized spin-1 Kagomé antiferromagnet
• Honeycomb antiferromagnet with a triply degenerate dimer ground state
• Spontaneous dimerization and moment formation in the Hida model of spin-1 kagomé antiferromagnet
• Low-temperature theory of inversion and quantum oscillations in Kondo insulators
• Exact staggered dimer ground state and its stability in a two-dimensional magnet
• Triplon mean-field analysis of an antiferromagnet with degenerate Shastry-Sutherland ground states
• Quantum to classical transition in the ground state of a spin-$S$ quantum antiferromagnet