Absence of a classical long-range order in $S=1/2$ Heisenberg antiferromagnet on triangular lattice

Abstract

We study the quantum phase transition of an $S=1/2$ anisotropic $\alpha$ $(\equiv J_z/J_{xy})$ Heisenberg antiferromagnet on a triangular lattice. We calculate the sublattice magnetization and the long-range helical order-parameter and their Binder ratios on finite systems with $N\le 36$ sites. The $N$ dependence of the Binder ratios reveals that the classical 120${}^{\circ }$ Néel state occurs for $\alpha \lesssim 0.55$, whereas a critical collinear state occurs for $1/\alpha \lesssim 0.6$. This result is at odds with a widely-held belief that the ground state of a Heisenberg antiferromagnet is the 120${}^{\circ }$ Néel state, but it also provides a possible mechanism explaining experimentally observed spin liquids.

4 pages, 7 figures

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• Amperean Pairing Instability in the U(1) Spin Liquid State with Fermi Surface and Application to $\kappa -(BEDT-TTF{)}_{2}C{u}_2(CN{)}_3$
• Spin liquid behaviour in Jeff=1/2 triangular lattice Ba3IrTi2O9
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Cited by in corpus (2)

• Signatures of indirect K-edge resonant inelastic x-ray scattering on magnetic excitations in triangular lattice antiferromagnet
• Magnetic order, spin waves and fluctuations in the triangular antiferromagnet La2Ca2MnO7