Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2
Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2
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DOI：
10.1038/s41567-020-0816-x
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发表时间：
2020-03-16
期刊：
影响因子：
19.6
通讯作者：
Hunt, Benjamin M.
中科院分区：
文献类型：
--
作者：
Lupke, Felix;Waters, Dacen;Hunt, Benjamin M.
产生拓扑量子计算的马约拉纳费米子的一种方法是在其他拓扑状态中诱导超导性。量子自旋霍尔绝缘体的特征在于二维（2D）内部的带隙和螺旋状的1D边缘态（1-3）。在螺旋边缘状态中诱导超导性导致了一维拓扑超导体，这是一种备受追捧的物质状态，是许多拓扑量子计算建议的核心（4）。在本研究中，我们报告了超导性和量子自旋霍尔边缘态共存的货车范德华异质结构，通过放置单层的1 T '-WTe 2，量子自旋霍尔绝缘体（1-3），在一个货车范德华超导体，NbSe 2。使用扫描隧道显微镜和光谱（STM/STS），我们表明，WTe 2单层表现出邻近诱导的超导间隙由于底层超导体和量子自旋霍尔边缘状态的光谱特征保持不变。总之，这些观察结果提供了确凿的证据，邻近诱导超导量子自旋霍尔边缘状态在WTe 2，实现一维拓扑超导性和马约拉纳束缚态在这个货车的材料平台的关键一步。
One way of producing Majorana fermions for topological quantum computing is to induce superconductivity in other topological states. Here, the proximity effect does this for the quantum spin Hall effect state in a 2D material.The quantum spin Hall insulator is characterized by a bandgap in the two-dimensional (2D) interior and helical 1D edge states(1-3). Inducing superconductivity in the helical edge state results in a 1D topological superconductor, a highly sought-after state of matter at the core of many proposals for topological quantum computing(4). In the present study, we report the coexistence of superconductivity and the quantum spin Hall edge state in a van der Waals heterostructure, by placing a monolayer of 1T '-WTe2, a quantum spin Hall insulator(1-3), on a van der Waals superconductor, NbSe2. Using scanning tunnelling microscopy and spectroscopy (STM/STS), we demonstrate that the WTe2 monolayer exhibits a proximity-induced superconducting gap due to the underlying superconductor and that the spectroscopic features of the quantum spin Hall edge state remain intact. Taken together, these observations provide conclusive evidence for proximity-induced superconductivity in the quantum spin Hall edge state in WTe2, a crucial step towards realizing 1D topological superconductivity and Majorana bound states in this van der Waals material platform.