Two-step melting of three-sublattice order in S = 1 easy-axis triangular lattice antiferromagnets★
Department of Physics, University of Toronto,
M5S 1A7, Canada
2 Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
a e-mail: firstname.lastname@example.org
Published online: 12 September 2018
We consider S = 1 triangular lattice Heisenberg antiferromagnets with a strong single-ion anisotropy D that dominates over the nearest-neighbour antiferromagnetic exchange J. In this limit of small J∕D, we study low temperature (T ~ J ≪ D) properties of such magnets by employing a low-energy description in terms of hard-core bosons with nearest neighbour repulsion V ≈ 4J + J2∕D and nearest neighbour unfrustrated hopping t ≈ J2∕2D. Using a cluster Stochastic Series Expansion (SSE) algorithm to perform sign-problem-free quantum Monte Carlo (QMC) simulations of this effective model, we establish that the ground-state three-sublattice order of the easy-axis spin-density Sz(r) melts in zero field (B = 0) in a two-step manner via an intermediate temperature phase characterized by power-law three-sublattice order with a temperature dependent exponent η(T)∈[1/9,1/4]. For η(T)<2/9 in this phase, we find that the uniform easy-axis susceptibility of an L × L sample diverges as χL ~ L2−9η at B = 0, consistent with recent predictions that the thermodynamic susceptibility to a uniform field B along the easy axis diverges at small B as χeasy-axis(B)~B−4−18η/4−9η in this regime.
© EDP Sciences / Società Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2018