Ising-type Antiferromagnets: Model Systems in Statistical Physics
Ising-type Antiferromagnets: Model Systems in Statistical Physics
复制标题
伊辛型反铁磁体：统计物理中的模型系统
DOI：
10.1007/978-3-540-45001-6_2
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
C. Binek
中科院分区：
文献类型：
--
作者：
C. Binek
本章指出了具有局域磁矩的绝缘离子化合物在统计物理领域的影响。它们是各向异性海森堡系统的完美实现，在单离子各向异性强的情况下，可以实现伊辛型模型系统。这种涉及强直接铁磁交换和附加弱反铁磁相互作用的化合物被证明是低维伊辛铁磁体的最佳模型系统之一。fec2是这些原型系统的代表，它提供了对基本热力学性质的实验途径，特别是李和杨的统计理论。从实验的角度简要介绍了李—杨理论，从等温磁化数据确定了三角形晶格上二维伊辛铁磁体配分函数复零的密度函数和间隙指数。最后，简要讨论了李杨理论以外的现代研究方法。引入了复温度平面上的费雪零点。推导了圆定理的一个可能的简单基础，并简要讨论了李-杨理论在非平衡系统领域的意义。
This chapter points out the impact of insulating ionic compounds with localized magnetic moments in the field of statistical physics. They are perfect realizations of anisotropic Heisenberg systems which, in the case of strong single-ion anisotropy, enable the realization of Ising-type model systems. Such compounds involving strong direct ferromagnetic exchange and additional weak antiferromagnetic interaction turn out to be among the best available model systems of low-dimensional Ising ferromagnets. FeCl2is a representative of these prototypical systems which provides experimental access to fundamental thermodynamic properties in general and the statistical theory of Lee and Yang in particular. Starting with a brief introduction of the Lee--Yang theory from an experimentalist's point of view, density functions of the complex zeros of the partition function as well as the gap exponent of the 2d Ising ferromagnet on a triangular lattice are determined from isothermal magnetization data. Finally, modern approaches beyond the Lee--Yang theory are briefly discussed. Fisher's zeros in the complex temperature plane are introduced. A possible simple basis underlying the circle theorem is motivated and implications from the Lee-Yang theory in the field of non-equilibrium systems are briefly discussed.