Resonating-Valence-Bond Ground-state of CaV${}_4$O${}_9$ by the Gutzwiller-projected Schwinger-boson method

Abstract

An antiferromagnetic Heisenberg model on a 1/5-depleted two-dimensional square-lattice, a model of CaV${}_4$O${}_9$, is investigated by variational Monte Carlo simulation. A prototype of a trial wave function is made by projecting out the doubly occupied states from the Schwinger-boson mean-field solution. Then variational Monte Carlo simulation is performed up to $40\times 40$ sites(including $320$ vacant sites). The optimized state has the lowest energy, $-0.5510J$, ever reported. For this state energies of a dimer bond and a plaquette bond, staggered magnetization, static structure factor, and excitation spectrum are calculated. It is shown that the Néel order survives and there is no gap at isotropic coupling.

10 pages(including figure captions) RevTex3.0, 4 figures, available upon request

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• Phase diagram of depleted Heisenberg model for CaV4O9
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Cited by in corpus (6)

• Exchange interactions and magnetic properties of the layered vanadates CaV2O5, MgV2O5, CaV3O7 and CaV4O9
• Frustrated quantum magnets
• The Heisenberg model on the 1/5-depleted square lattice and the CaV4O9 compound
• Meta-Plaquette Expansion for the Triplet Excitation Spectrum in CaV${}_4$O${}_9$
• Magnetic Susceptibility for $Ca{V}_4{O}_9$
• Orbital Order Effect of Two-Dimensional Spin Gap System for CaV4O9