Low-Temperature Properties of the Heisenberg Antiferromagnets on the Layered Triangular Lattice

Abstract

The low-temperature properties of the Heisenberg antiferromagnets on the layered triangular lattice with antiferromagnetic (J > 0) interaction between spins within layer and antiferromagnetic (J⊥ > 0) and ferromagnetic (J⊥ < 0) interactions between layers are studied by using a linear spin-wave theory. The staggered magnetization and specific heat are calculated for different interlayer interactions. It is found that the staggered magnetization at zero temperature increases faster and the ground state energy decreases slower for ferromagnetic interlayer interaction than those for antiferromagnetic interlayer interaction with the interlayer interaction increasing. At low temperatures, the reduction effects of the interlayer interactions to the spin thermal fluctuation are similar for the same antiferromagnetic and ferromagnetic interlayer interactions, and the temperature dependences of the staggered magnetization and specific heat follow the laws of Δ〈Sz〉 ∝ — T2, Cm ∝ T3, respectively.