论文标题
高阶拓扑绝缘子WTE2中的透明约瑟夫森连接通过PD扩散
Transparent Josephson Junctions in Higher-Order Topological Insulator WTe2 via Pd Diffusion
论文作者
论文摘要
与拓扑绝缘子（TI）高度透明的超导接触（TI）在工程师拓扑超导性的途径上仍然是一个持续的挑战。最近，显示在钯（PD）底部触点上时，显示了高阶$ _2 $ $ _2 $，在追求这一目标时证明了有希望的材料系统。在这里，我们将PD扩散到WTE $ _2 $中，并将超导PDTE $ _x $的形成作为观察到的超导性的起源。我们在垂直方向上找到了一个原子尖锐的界面，与扩散晶体及其宿主晶体之间的范德华层层，形成了与Ti的最新超导接触。发现扩散沿wte $ _2 $晶体的宽度是不均匀的，与整体相比，边缘沿边缘延伸更大。这种接触方法的潜力通过采用外部超导导线在约瑟夫森连接的运输测量中突出显示。
Highly transparent superconducting contacts to a topological insulator (TI) remain a persistent challenge on the route to engineer topological superconductivity. Recently, the higher-order TI WTe$_2$ was shown to turn superconducting when placed on palladium (Pd) bottom contacts, demonstrating a promising material system in pursuing this goal. Here, we report the diffusion of Pd into WTe$_2$ and the formation of superconducting PdTe$_x$ as the origin of observed superconductivity. We find an atomically sharp interface in vertical direction to the van der Waals layers between the diffusion crystal and its host crystal, forming state-of-the-art superconducting contacts to a TI. The diffusion is discovered to be non-uniform along the width of the WTe$_2$ crystal, with a greater extend along the edges compared to the bulk. The potential of this contacting method is highlighted in transport measurements on Josephson junctions by employing external superconducting leads.
