Mean-field study of the disordered ground state in the beta-Mn lattics.
Mean-field study of the disordered ground state in the beta-Mn lattics.
复制标题
β-Mn 晶格中无序基态的平均场研究。
DOI：
10.1103/physrevb.61.11251
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
C. Lacroix
中科院分区：
文献类型：
--
作者：
B. Canals;C. Lacroix
锰β相中ii型原子形成立方对称的共享角三角形三维网络。这种奇特的几何结构引起了非常强烈的拓扑挫败感，这可以解释锰β相中缺乏磁有序。在平均场理论中，我们证明了具有最近邻相互作用的经典反铁磁海森堡模型呈现出一条零能量模式线。因此，在平均场近似中，该模型在晶格上的任何温度下都不有序。较长距离的相互作用或轻微的变形并不总是消除基态简并，并且模型只会对特殊的交换参数集进行排序。
The type-II atoms in the β phase of manganese form a three-dimensional network of corner-sharing triangles in a cubic symmetry. This peculiar geometry induces a very strong topological frustration that can explain the absence of magnetic ordering in the β phase of manganese. Within a mean-field theory, we show that the classical antiferromagnetic Heisenberg model with nearest-neighbor interactions exhibits a line of zero energy modes. Thus this model does not order at any temperature on this lattice in the mean-field approximation. Longer-range interactions or slight deformations do not always remove the ground-state degeneracy, and the model will order only for peculiar sets of exchange parameters.