Low-energy properties of two-dimensional quantum triangular antiferromagnets: Nonperturbative renormalization group approach
Low-energy properties of two-dimensional quantum triangular antiferromagnets: Nonperturbative renormalization group approach
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DOI：
10.1103/physrevb.73.184401
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发表时间：
2005-11
影响因子：
3.7
通讯作者：
S. Fujimoto
中科院分区：
文献类型：
--
作者：
S. Fujimoto
研究了二维量子三角海森堡反铁磁体在零温量子相变附近的低温性质。利用SO（3）× SO（2）/SO（2）矩阵Ginzburg-Landau-Wilson模型描述的有效场论和非微扰重整化群方法，阐明了量子涨落和热涨落如何影响系统在参数区域的长波行为，在该区域系统表现出涨落驱动的一级跃迁到长程有序态.我们发现在有限温度下，量子理论与重整化二维经典非线性σ模型区域之间出现了交叉，在这个交叉区域中，具有线性色散的无质量涨落模和自旋波支配着低能物理.我们的结果与最近对二维三角形海森堡自旋系统NiGa 2S 4的实验观察符合得很好。
We explore low temperature properties of quantum triangular Heisenberg antiferromagnets in two dimension in the vicinity of the quantum phase transition at zero temperature. Using the effective field theory described by the $SO(3)\times SO(2)/SO(2)$ matrix Ginzburg-Landau-Wilson model and the non-perturbative renormalization group method, we clarify how quantum and thermal fluctuations affect long-wavelength behaviors in the parameter region where the systems exhibit a fluctuation-driven first order transition to a long-range ordered state. We show that at finite temperatures the crossover from a quantum $\phi^6$ theory to a renormalized two-dimensional classical nonlinear sigma model region appears, and in this crossover region, massless fluctuation modes with linear dispersion a la spin waves govern low-energy physics. Our results are in good agreement with the recent experimental observations for the two-dimensional triangular Heisenberg spin system, NiGa$_2$S$_4$.