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

作者：Suzuki Nobuo^*; Matsubara Fumitaka; Fujiki Sumiyoshi; Shirakura Takayuki

来源：Physical Review B, 2014, 90(18): 184414.

DOI：10.1103/PhysRevB.90.184414

We study the quantum phase transition of an S = 1/2 anisotropic alpha (= 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 <= 36 sites. The N dependence of the Binder ratios reveals that the classical 120 degrees Neel state occurs for alpha <= 0.55, whereas a critical collinear state occurs for 1/alpha <= 0.6. This result is at odds with a widely held belief that the ground state of a Heisenberg antiferromagnet is the 120 degrees Neel state, but it also provides a possible mechanism explaining experimentally observed spin liquids.

• 出版日期2014-11-14