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arXiv 1310.4580cond-mat.str-elcond-mat.stat-mech
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几何阻挫格点上Kondo格点模型的不变能级和平带工程

Invariant Energy Levels and Flat Band Engineering in a Kondo Lattice Model on Geometrically Frustrated Lattices

Masafumi Udagawa, Hiroaki Ishizuka, Yukitoshi Motome

摘要:

我们证明了在Kondo晶格模型中,在孤立的完全图(如三角形和四面体)上存在不变的能级。这些能级总是具有固定的本征能量$t \pm J/2$,而与局域矩的配置无关($t$是传导电子的转移积分,$J$是自旋-电荷耦合常数)。我们还扩展到几何挫折格的分析,使用完全图作为基本的积木。我们表明,不变的能级的建设规则导致的局域化状态的存在条件,如果该模型是基于三角形的线图,如一个kagome晶格定义。我们进一步提出了一个工程的孤立的平带的时间反演对称性破缺,这是从其他色散带与有限的能隙分开的过程。

英文摘要:

We show the existence of invariant energy levels in a Kondo lattice model on an isolated complete graph, such as a triangle and a tetrahedron. These energy levels always have fixed eigenenergies $t \pm J/2$, irrespective of the configuration of localized moments ($t$ is the transfer integral of conduction electrons and $J$ is the spin-charge coupling constant). We also extend the analysis to geometrically frustrated lattices by using the complete graphs as basic building blocks. We show that the construction rule for the invariant energy levels leads to the existence condition of localized states, if the model is defined on the triangle-based line graphs, such as a kagome lattice. We further propose a procedure of engineering isolated flat bands with broken time-reversal symmetry, which are separated from other dispersive bands with finite energy gaps.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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