The topic of two-dimensional topological insulators has blossomed after the first observation of the quantum spin Hall (QSH) effect in HgTe quantum wells. However, studies have been hindered by the relative fragility of the edge states. Their stability has been a subject of both theoretical and experimental investigation in the past decade. Here, we present a new generation of high quality (Cd,Hg)Te/HgTe-structures based on a new chemical etching method. From magnetotransport measurements on macro- and microscopic Hall bars, we extract electron mobilities μ up to about 400 × 10³ cm²/(V s), and the mean free path λ_mfp becomes comparable to the sample dimensions. The Hall bars show quantized spin Hall conductance, which is remarkably stable up to 15 K. The clean and robust edge states allow us to fabricate high quality side-contacted Josephson junctions, which are significant in the context of topological superconductivity. Our results open up new avenues for fundamental research on QSH effect as well as potential applications in spintronics and topological quantum computation.

中文翻译：

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用于量子自旋霍尔研究的高迁移率HgTe微结构

在首次观察到HgTe量子阱中的量子自旋霍尔（QSH）效应之后，二维拓扑绝缘体这一话题开始兴起。但是，边缘状态的相对脆弱性阻碍了研究。在过去的十年中，其稳定性一直是理论和实验研究的主题。在这里，我们介绍了基于新的化学蚀刻方法的新一代高质量（Cd，Hg）Te / HgTe结构。通过在宏观和微观霍尔棒上的磁传输测量，我们提取出电子迁移率μ，最高可达约400×10 ³  cm ² /（V s），并且平均自由程_λmfp变得与样本尺寸可比。霍尔棒显示量化的自旋霍尔电导，在高达15 K的情况下非常稳定。干净而稳固的边缘状态使我们能够制造高质量的侧接触约瑟夫森结，这在拓扑超导电性的背景下非常重要。我们的研究结果为QSH效应的基础研究以及自旋电子学和拓扑量子计算的潜在应用开辟了新途径。