Quantized surface transport in topological Dirac semimetal films
Quantized surface transport in topological Dirac semimetal films
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DOI：
10.1038/s41467-019-10499-0
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发表时间：
2019-06-12
影响因子：
16.6
通讯作者：
Kawasaki, Masashi
中科院分区：
文献类型：
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作者：
Nishihaya, Shinichi;Uchida, Masaki;Kawasaki, Masashi
由非平凡体序保护的非常规表面态是拓扑材料中各种奇异量子输运的来源。一个突出的例子是独特的磁轨道，即所谓的Weyl轨道，在拓扑半金属中，两个空间分离的表面费米弧在整体上相互连接。最近对Dirac半金属Cd3As2块体中量子霍尔态的观测引起了人们对可能从Weyl轨道演变而来的新型量子化现象的关注。在这里，我们报道了Cd3As2薄膜样品中的表面量子振荡及其向量子霍尔态的演化，其中体维，费米能量和能带拓扑被系统地控制。我们揭示了体态在量子化表面输运中的本质参与以及由此产生的依赖于体占据的量子霍尔简并。我们在薄膜样品中控制表面输运的演示也为拓扑半金属中费米弧介导的输运工程铺平了道路。
Unconventional surface states protected by non-trivial bulk orders are sources of various exotic quantum transport in topological materials. One prominent example is the unique magnetic orbit, so-called Weyl orbit, in topological semimetals where two spatially separated surface Fermi-arcs are interconnected across the bulk. The recent observation of quantum Hall states in Dirac semimetal Cd3As2 bulks have drawn attention to the novel quantization phenomena possibly evolving from the Weyl orbit. Here we report surface quantum oscillation and its evolution into quantum Hall states in Cd3As2 thin film samples, where bulk dimensionality, Fermi energy, and band topology are systematically controlled. We reveal essential involvement of bulk states in the quantized surface transport and the resultant quantum Hall degeneracy depending on the bulk occupation. Our demonstration of surface transport controlled in film samples also paves a way for engineering Fermi-arc-mediated transport in topological semimetals.