RKKY coupling in Weyl semimetal thin films
RKKY coupling in Weyl semimetal thin films
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DOI：
10.1103/physrevb.101.085419
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发表时间：
2019-08
影响因子：
3.7
通讯作者：
Sonu Verma;D. Giri;H. Fertig;A. Kundu
中科院分区：
文献类型：
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作者：
Sonu Verma;D. Giri;H. Fertig;A. Kundu
在Ruderman-Kittel-Kasuya-Yoshida(RKKY)理论下，我们考虑了薄膜Weyl半金属表面杂质自旋之间的有效耦合。如果自旋在同一表面上，它们的耦合反映了费米弧的各向异性和自旋-动量锁定。相反，当自旋在相反的表面上时，它们的耦合是由费米弧和体态来调节的。在这种情况下，耦合既令人惊讶地强烈，又强烈地依赖于厚度，最大值在最佳厚度处。我们使用薄膜几何中态的解析解，以及紧束缚模型的两面递归格林函数分析来证明我们的结果。
We consider the effective coupling between impurity spins on surfaces of a thin-film Weyl semimetal within Ruderman-Kittel-Kasuya-Yoshida (RKKY) theory. If the spins are on the same surface, their coupling reflects the anisotropy and the spin-momentum locking of the Fermi arcs. By contrast when the spins are on opposite surfaces, their coupling is mediated by the Fermi arcs as well as by bulk states. In this case the coupling is both surprisingly strong and strongly thickness dependent, with a maximum at an optimum thickness. We demonstrate our results using analytical solutions of states in the thin-film geometry, as well using a two-surface recursive Green's function analysis of the tight-binding model.