Noncoplanar magnetic ordering driven by itinerant electrons on the pyrochlore lattice.
Noncoplanar magnetic ordering driven by itinerant electrons on the pyrochlore lattice.
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由烧绿石晶格上的流动电子驱动的非共面磁排序。
DOI：
10.1103/physrevlett.105.226403
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发表时间：
2010
影响因子：
8.6
通讯作者：
G. Chern
中科院分区：
文献类型：
--
作者：
G. Chern
在旋转不变的自旋系统中，交换作用倾向于支持共线或共面磁序。事实上，这种磁结构通常是由高度受抑的磁体中的热或量子波动选择的。在这里，我们表明，一个复杂的非共面磁秩序的四重晶胞是稳定的巡回电子的烧绿石晶格。具体地说，我们考虑一个Kondo晶格模型与经典的本地化时刻在四分之一填充。在这个填充因子下的电子费米“表面”在拓扑学上等价于三个相交的费米圆。费米线的完美嵌套导致具有多个波矢量和确定的旋向性的磁有序。在有限温度下，手征自旋液体中的手征有序可以在没有磁有序的情况下持续存在。
Exchange interaction tends to favor collinear or coplanar magnetic orders in rotationally invariant spin systems. Indeed, such magnetic structures are usually selected by thermal or quantum fluctuations in highly frustrated magnets. Here we show that a complex noncoplanar magnetic order with a quadrupled unit cell is stabilized by itinerant electrons on the pyrochlore lattice. Specifically, we consider a Kondo-lattice model with classical localized moments at quarter filling. The electron Fermi "surface" at this filling factor is topologically equivalent to three intersecting Fermi circles. Perfect nesting of the Fermi lines leads to magnetic ordering with multiple wave vectors and a definite handedness. The chiral order might persist without magnetic order in a chiral spin liquid at finite temperatures.