The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study

Abstract

The phase transition of the quantum spin-1/2 frustrated Heisenberg antiferroferromagnet on an anisotropic square lattice is studied by using a variational treatment. The model is described by the Heisenberg Hamiltonian with two antiferromagnetic interactions: nearest-neighbor (NN) with different coupling strengths J_{1} and J_{1'} along x and y directions competing with a next-nearest-neighbor coupling J_{2} (NNN). The ground state phase diagram in the (λ,α) space, where λ=J_{1'}/J_{1} and α=J_{2}/J_{1}, is obtained. Depending on the values of λ and α, we obtain three different states: antiferromagnetic (AF), collinear antiferromagnetic (CAF) and quantum paramagnetic (QP). For an intermediate region λ_{1}<λ<1 we observe a QP state between the ordered AF and CAF phases, which disappears for λ above some critical value λ_{1}. The boundaries between these ordered phases merge at the quantum critical endpoint (QCE). Below this QCE there is again a direct first-order transition between the AF and CAF phases, with a behavior approximately described by the classical line α_{c}{\simeq}λ/2.

References in corpus (13)

• Ground-state phases of the spin-1/2 J_1-J_2 Heisenberg antiferromagnet on the square lattice: A high-order coupled cluster treatment
• The J1-J2 model: First order phase transition versus deconfinement of spinons
• Hierarchical mean-field approach to the $J_1$-$J_2$ Heisenberg model on a square lattice
• Extension of the spin-1/2 frustrated square lattice model: the case of layered vanadium phosphates
• Coupled Cluster Treatment of the Shastry-Sutherland Antiferromagnet
• Effect of anisotropy on the ground-state magnetic ordering of the spin-half quantum $J_1^{XXZ}$--$J_2^{XXZ}$ model on the square lattice
• Nonlinear Sigma model method for the J1-J2 Heisenberg model: disordered ground state with plaquette symmetry
• Ising transition in the two-dimensional quantum $J_1-J_2$ Heisenberg model
• Second-order quantum corrections for the frustrated, spatially anisotropic, spin-1/2 Heisenberg antiferromagnet on a square lattice
• Effects of ring exchange interaction on the Neel phase of two-dimensional, spatially anisotropic, frustrated Heisenberg quantum antiferromagnet
• The Ising phase in the J1-J2 Heisenberg Model
• Magnetic phase diagram of spatially anisotropic, frustrated spin-1/2 Heisenberg antiferromagnet on a stacked square lattice
• The ground-state magnetic ordering of the spin-1/2 frustrated J1-J2 XXZ model on the square lattice