Itinerant Electron-Driven Chiral Magnetic Ordering and Spontaneous Quantum Hall Effect in Triangular Lattice Models
Itinerant Electron-Driven Chiral Magnetic Ordering and Spontaneous Quantum Hall Effect in Triangular Lattice Models
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DOI：
10.1103/physrevlett.101.156402
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发表时间：
2008-10-10
影响因子：
8.6
通讯作者：
Batista, C. D.
中科院分区：
文献类型：
--
作者：
Martin, Ivar;Batista, C. D.
我们研究了三角形晶格上的Kondo晶格和Hubbard模型。我们发现在平均场水平上，这些旋转不变模型自然地支持非共面手性磁有序。在带填充因子3/4处表现为弱耦合不稳定性，这是由于流动电子费米表面的完美嵌套。这种排序是发生在半填充方形晶格上的共线尼尔排序的三角晶格对应物。当长程磁有序被热波动破坏时，手性可以持续到有限的温度，在没有任何外部施加磁场的情况下引起自发的量子霍尔效应。
We study the Kondo Lattice and the Hubbard models on a triangular lattice. We find that at the mean-field level, these rotationally invariant models naturally support a noncoplanar chiral magnetic ordering. It appears as a weak-coupling instability at the band filling factor 3/4 due to the perfect nesting of the itinerant electron Fermi surface. This ordering is a triangular-lattice counterpart of the collinear Neel ordering that occurs on the half-filled square lattice. While the long-range magnetic ordering is destroyed by thermal fluctuations, the chirality can persist up to a finite temperature, causing a spontaneous quantum Hall effect in the absence of any externally applied magnetic field.