Revisiting a variational study of the quantum spin-1/2 J^sub 1^ - J'^sub 1^ - J^sub 2^ Heisenberg antiferromagnet

The variational study of the ground state of the spin-1/2 anisotropic Heisenberg antiferromagnet has been revisited on a square lattice by improving and correcting past numerical results. The Hamiltonian has been implemented on a square lattice with antiferromagnetic interactions between nearest- an...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2019-01, Vol.469, p.650
Main Authors: Vidarte, Kevin J Urcia, Nunura, Luigui A Chero, Salmon, Octavio D Rodriguez, de Sousa, José Ricardo
Format: Article
Language:English
Subjects:
Antiferromagnetism
Couplings
Lattice theory
Magnetism
Phase diagrams
Phase transitions
Quantum physics
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Summary:The variational study of the ground state of the spin-1/2 anisotropic Heisenberg antiferromagnet has been revisited on a square lattice by improving and correcting past numerical results. The Hamiltonian has been implemented on a square lattice with antiferromagnetic interactions between nearest- and next-nearest neighbors. The nearest-neighbor couplings have different strengths, namely, J1 and J'1, for the x and y directions, respectively. These couplings compete with the next-nearest ones denoted by J2. We obtained a new phase diagram in the λ - α plane, where λ =J'1/J1 and α = J2/J1, whose topology is slightly different of that previously found. There is no direct frontier dividing the collinear (CAF) and the antiferromagnetic (AF) order, rather, the quantum paramagnetic phase (QP) separates these two phases for all positive values of λ and α. The true nature of the frontiers has been obtained by scanning rigorously the relevant points of the λ - α plane.
ISSN:0304-8853
1873-4766