Ferromagnetic-electrodes-induced Hall effect in topological Dirac semimetals
Ferromagnetic-electrodes-induced Hall effect in topological Dirac semimetals
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DOI：
10.1103/physrevresearch.3.033023
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发表时间：
2020-09
影响因子：
4.2
通讯作者：
Koji Kobayashi;K. Nomura
中科院分区：
文献类型：
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作者：
Koji Kobayashi;K. Nomura
提出了一种具有铁磁电极的拓扑狄拉克半金属中的非传统霍尔效应。拓扑狄拉克半金属本身具有时间反转对称性，而附加的铁磁电极破坏了它，导致了大的霍尔响应。这种诱导霍尔效应是拓扑狄拉克半金属的螺旋表面态和量子自旋霍尔绝缘体的螺旋边态的特征。我们用四端几何的晶格模型计算了霍尔电导/电阻和霍尔角。对于具有四个电极的拓扑狄拉克半金属，无论电流电极还是电压电极都是铁磁性的，都会发生感生霍尔效应。当电极中的自旋几乎完全极化时，霍尔角变得与量子霍尔态或理想磁性Weyl半金属的霍尔角一样大。我们展示了诱导霍尔效应对杂质的稳健性，并讨论了自旋注入和自旋衰减问题。这种霍尔响应可以用来检测两个铁磁电极的磁化是平行的还是反平行的。
We propose an unconventional type of Hall effect in a topological Dirac semimetal with ferromagnetic electrodes. The topological Dirac semimetal itself has time-reversal symmetry, whereas attached ferromagnetic electrodes break it, causing the large Hall response. This induced Hall effect is a characteristic of the helical surface states of topological Dirac semimetals and the helical edge states of quantum spin Hall insulators. We compute the Hall conductance/resistance and the Hall angle by using a lattice model with four-terminal geometry. For topological Dirac semimetals with four electrodes, the induced Hall effect occurs whether the current electrodes or the voltage electrodes are ferromagnetic. When the spins in electrodes are almost fully polarized, the Hall angle becomes as large as that of quantum Hall states or ideal magnetic Weyl semimetals. We show the robustness of the induced Hall effect against impurities and also discuss the spin injection and spin decay problems. This Hall response can be used to detect whether the magnetizations of the two ferromagnetic electrodes are parallel or antiparallel.