Tunable charged domain wall from topological confinement in nodal-line semimetals
Tunable charged domain wall from topological confinement in nodal-line semimetals
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DOI：
10.1103/physrevb.101.081102
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发表时间：
2019-05
影响因子：
3.7
通讯作者：
A. Sekine;N. Nagaosa
中科院分区：
文献类型：
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作者：
A. Sekine;N. Nagaosa
我们从理论上研究了拓扑节线半金属的电子结构。我们表明，在存在形成畴壁的开隙空间相关质量项的情况下，在畴壁处出现间隙内带电局域模式。事实证明，这种畴壁是通过头对头（或尾对尾）体电极化来实现的。随着体带隙的增加，局域模式的色散从无带隙演变为带隙，这意味着其电导率是可调的。局域模态具有拓扑起源，即实现了拓扑约束，这可以通过半经典动量实数空间中定义的半经典拓扑数来理解。与之前的研究相比，本研究中带电畴壁的起源是纯电子的，即由于能带拓扑。此外，这项研究证明了两个绝缘体之间的界面处存在拓扑限制，而没有大量的拓扑数。我们讨论了稳定、电可调带电畴壁的可能实验实现。
We study theoretically the electronic structure of topological nodal-line semimetals. We show that, in the presence of a gap-opening spatially dependent mass term that forms a domain wall, an in-gap charged localized mode emerges at the domain wall. It turns out that such a domain wall is realized by head-to-head (or tail-to-tail) bulk electric polarizations. The dispersion of the localized mode evolves from gapless to gapped as the bulk band gap increases, which means that its conductivity is tunable. The localized mode has a topological origin, i.e., a topological confinement is realized, which is understood by a semiclassical topological number defined in semiclassical momentum-real space. In contrast to previous studies, the origin of the charged domain wall in this study is purely electronic, i.e., due to the band topology. Moreover, this study demonstrates a topological confinement at the interface between two insulators without bulk topological numbers. We discuss a possible experimental realization of the stable, electrically tunable charged domain wall.