Department of Physics, Kharkov National University, 61077 Kharkov, Ukraine.
J Phys Condens Matter. 2011 Apr 27;23(16):164209. doi: 10.1088/0953-8984/23/16/164209. Epub 2011 Apr 6.
We investigate the effect of geometrical frustration on the H-T phase diagrams of the classical Heisenberg antiferromagnets on triangular and kagome lattices. The phase diagrams for the two models are obtained from large-scale Monte Carlo simulations. For the kagome antiferromagnet, thermal fluctuations are unable to lift degeneracy completely and stabilize translationally disordered multipolar phases. We find a substantial difference in the temperature scales of the order by disorder effect related to different degeneracy of the low- and the high-field classical ground states in the kagome antiferromagnet. In the low-field regime, the Kosterlitz-Thouless transition into a spin-nematic phase is produced by unbinding of half-quantum vortices.
我们研究了几何各向异性对三角和 kagome 晶格上经典海森堡反铁磁体 H-T 相图的影响。这两个模型的相图是通过大规模蒙特卡罗模拟得到的。对于 kagome 反铁磁体，热涨落不能完全消除简并并稳定平移无序的多极相。我们发现，与低场和高场经典基态不同简并度相关的无序效应的有序温度标度在 kagome 反铁磁体中有很大的差异。在低场 regime 下，通过半量子涡旋的解缚产生进入自旋向列相的科斯特利茨-图卢兹转变。
