Li Hailong, Liu Haiwen, Jiang Hua, Xie X C
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China.
Phys Rev Lett. 2020 Jul 17;125(3):036602. doi: 10.1103/PhysRevLett.125.036602.
We investigate the 3D quantum Hall effect in Weyl semimetals and elucidate a global picture of the edge states. The edge states hosting 3D quantum Hall effect are combinations of Fermi arcs and chiral Landau bands dispersing along the magnetic field direction. The Hall conductance, σ_{xz}^{H} [see Fig. 4], shows quantized plateaus with the variance of the magnetic field when the Fermi level is at the Weyl node. However, the chiral Landau bands can change the spatial distribution of the edge states, especially under a tilted magnetic field, and the resulting edge states lead to distinctive Hall transport phenomena. A tilted magnetic field contributes an intrinsic value to σ_{xz}^{H} and such an intrinsic value is determined by the tilting angle θ between the magnetic field and the y axis [see Fig. 1(c)]. Particularly, even if the perpendicular magnetic field is fixed, σ_{xz}^{H} will change its sign with an abrupt spatial shift of the edge states when θ exceeds a critical angle θ_{c}. Our work uncovers the novel edge-state nature of the 3D quantum Hall effect in Weyl semimetals.
我们研究了外尔半金属中的三维量子霍尔效应，并阐明了边缘态的整体图像。承载三维量子霍尔效应的边缘态是费米弧和沿磁场方向色散的手性朗道带的组合。当费米能级位于外尔节点时，霍尔电导σ_{xz}^{H} [见图4] 显示出随磁场变化的量子化平台。然而，手性朗道带可以改变边缘态的空间分布，特别是在倾斜磁场下，由此产生的边缘态导致独特的霍尔输运现象。倾斜磁场对σ_{xz}^{H} 贡献一个本征值，该本征值由磁场与y轴之间的倾斜角θ决定 [见图1(c)]。特别地，即使垂直磁场固定，当θ超过临界角θ_{c} 时，σ_{xz}^{H} 也会随着边缘态的突然空间移动而改变其符号。我们的工作揭示了外尔半金属中三维量子霍尔效应的新型边缘态性质。
