Veyrat Arthur, Labracherie Valentin, Bashlakov Dima L, Caglieris Federico, Facio Jorge I, Shipunov Grigory, Charvin Titouan, Acharya Rohith, Naidyuk Yurii, Giraud Romain, van den Brink Jeroen, Büchner Bernd, Hess Christian, Aswartham Saicharan, Dufouleur Joseph
Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, D-01069Dresden, Germany.
B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine (NASU), 47 Nauky Avenue, 61103Kharkiv, Ukraine.
Nano Lett. 2023 Feb 22;23(4):1229-1235. doi: 10.1021/acs.nanolett.2c04297. Epub 2023 Jan 31.
Symmetry breaking in topological matter has become in recent years a key concept in condensed matter physics to unveil novel electronic states. In this work, we predict that broken inversion symmetry and strong spin-orbit coupling in trigonal PtBi lead to a type-I Weyl semimetal band structure. Transport measurements show an unusually robust low dimensional superconductivity in thin exfoliated flakes up to 126 nm in thickness (with ∼ 275-400 mK), which constitutes the first report and study of unambiguous superconductivity in a type-I Weyl semimetal. Remarkably, a Berezinskii-Kosterlitz-Thouless transition with ∼ 310 mK is revealed in up to 60 nm thick flakes, which is nearly an order of magnitude thicker than the rare examples of two-dimensional superconductors exhibiting such a transition. This makes PtBi an ideal platform to study low dimensional and unconventional superconductivity in topological semimetals.
近年来，拓扑物质中的对称性破缺已成为凝聚态物理中揭示新型电子态的关键概念。在这项工作中，我们预测三角结构的PtBi中反演对称性的破缺和强自旋轨道耦合会导致I型外尔半金属能带结构。输运测量表明，在厚度达126纳米的薄片状剥离样品中存在异常稳健的低维超导性（转变温度约为275 - 400 mK），这是首次关于I型外尔半金属中明确超导性的报道和研究。值得注意的是，在厚度达60纳米的薄片中发现了转变温度约为310 mK的 Berezinskii - Kosterlitz - Thouless 转变，这比表现出这种转变的二维超导体的罕见例子厚了近一个数量级。这使得PtBi成为研究拓扑半金属中低维和非常规超导性的理想平台。
