Spontaneous symmetry breaking in topological matter has emerged as a pivotal concept in describing phase transitions within condensed-matter physics. Of particular interest is the Berezinskii-Kosterlitz-Thouless (BKT) transition observed in two-dimensional superconductors. Here, we present comprehensive transport experiments on a nanoflake of the topological nodal-line semimetal ${\mathrm{SnTaS}}_2$ with a thickness of about 37 nm, revealing its hosting of a superconducting state with an onset transition temperature of 2.7 K. Temperature-dependent upper critical fields reveal an anisotropic superconductivity. Angle-dependent magnetotransport and the BKT transition confirm quasi-two-dimensional superconductivity in the ${\mathrm{SnTaS}}_2$ nanoflake. Given the presence of spin-polarized surface states in ${\mathrm{SnTaS}}_2$, these findings establish a novel platform for exploring topological superconductivity and Majorana modes.

中文翻译：

---

拓扑节点线半金属 SnTaS2 纳米片的准二维超导性


拓扑物质中的自发对称性破缺已成为描述凝聚态物理学中相变的关键概念。特别令人感兴趣的是在二维超导体中观察到的 Berezinskii-Kosterlitz-Thouless (BKT) 转变。在这里，我们提出了拓扑节点线半金属纳米片的综合输运实验 ${\mathrm{SnTaS}}_2$ 厚度约为 37 nm，显示其具有超导态，起始转变温度为 2.7 K。温度相关的上临界场显示出各向异性超导性。角度相关的磁输运和 BKT 跃迁证实了准二维超导性 ${\mathrm{SnTaS}}_2$ 纳米片。鉴于自旋极化表面态的存在 ${\mathrm{SnTaS}}_2$ ，这些发现为探索拓扑超导和马约拉纳模式建立了一个新颖的平台。