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arXiv 1502.01201cond-mat.mes-hallcond-mat.str-el
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螺旋液体中RKKY相互作用的电控制和相互作用效应

Electrical control and interaction effects of the RKKY interaction in helical liquids

Yu-Wen Lee, Yu-Li Lee

摘要:

研究了在外加电场诱导的Rashba自旋轨道耦合和电子-电子相互作用下,量子自旋霍尔绝缘体螺旋边态介导的RKKY相互作用.我们发现,在Rashba耦合的存在下,由螺旋边缘态诱导的RKKY相互作用不仅包含Heisenberg类和Dzyaloshinskiiii-Moria项,而且还包含原来不存在的向列型项,范围函数取决于Rashba耦合的强度。我们还表明,电子-电子相互作用改变的RKKY相互作用的强度,通过修改的权力的$1/|x|$依赖的范围功能。特别地,通过改变相互作用或Rashba耦合的强度,存在涉及在Luttinger液体参数$K=1/2$的值处的RKKY相互作用的符号变化的(杂质)量子相变。由于Rashba耦合的强度和螺旋边缘态的化学势都可以通过外部栅极电压进行电学控制,我们的结果不仅揭示了二维拓扑绝缘体边缘磁杂质关联的本质,而且为量子计算中操纵量子比特铺平了道路.

英文摘要:

We study the RKKY interaction mediated by the helical edge states of a quantum spin Hall insulator in the presence of the Rashba spin-orbital coupling induced by an external electric field and the electron-electron interaction. We show that in the presence of the Rashba coupling, the RKKY interaction induced by the helical edge states contains not only the Heisenberg-like and the Dzyaloshinskii-Moria terms but also the nematic-type term that is not present originally, with the range functions depending on the strength of the Rashba coupling. We also show that the electron-electron interaction changes the strength of the RKKY interaction by modifying the power of the $1/|x|$ dependence of the range functions. In particular, by varying the strength of the interaction or the Rashba coupling, there is an (impurity) quantum phase transition involving the sign change of the RKKY interaction at the value of the Luttinger liquid parameter $K=1/2$. Since both the strength of the Rashba coupling and the chemical potential of the helical edge states are electrically controllable by external gate voltages, our results not only shed light on the nature of magnetic impurity correlations in the edge of a two-dimensional topological insulator, but also pave a way to manipulate the qubits in quantum computing.

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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