Spin-glass transition in geometrically frustrated antiferromagnets with weak disorder
Spin-glass transition in geometrically frustrated antiferromagnets with weak disorder
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DOI：
10.1103/physrevb.81.014406
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发表时间：
2010-01-01
影响因子：
3.7
通讯作者：
Sherrington, D.
中科院分区：
文献类型：
--
作者：
Andreanov, A.;Chalker, J. T.;Sherrington, D.
我们研究了交换相互作用强度的弱随机变化对几何阻挫反铁磁体的影响。在没有无序的情况下，这些系统的最简单的经典模型具有宏观简并基态，这种简并可能阻止在任何温度下的有序化。弱交换随机性有利于这些基态的一个小的子集，并诱导自旋玻璃化转变在一个有序的温度由相互作用强度的调制幅度确定。我们使用复制品的方法来制定这种转变的理论，表明它福尔斯落入相同的普适性类传统的自旋玻璃化转变。此外，我们表明，一个模型与低浓度的缺陷债券可以映射到一个系统的随机定位的pseudospins具有偶极有效的相互作用。我们还提出了详细的结果，从蒙特卡罗模拟的经典海森堡反铁磁体的烧绿石晶格在最近邻交换弱随机性。
We study the effect in geometrically frustrated antiferromagnets of weak, random variations in the strength of exchange interactions. Without disorder the simplest classical models for these systems have macroscopically degenerate ground states, and this degeneracy may prevent ordering at any temperature. Weak exchange randomness favors a small subset of these ground states and induces a spin-glass transition at an ordering temperature determined by the amplitude of modulations in interaction strength. We use the replica approach to formulate a theory for this transition, showing that it falls into the same universality class as conventional spin-glass transitions. In addition, we show that a model with a low concentration of defect bonds can be mapped onto a system of randomly located pseudospins that have dipolar effective interactions. We also present detailed results from Monte Carlo simulations of the classical Heisenberg antiferromagnet on the pyrochlore lattice with weak randomness in nearest-neighbor exchange.