1. Observation of Two-dimensional Superconductivity in an Ultrathin Iron-Arsenic Superconductor
- Author
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Zhang, Chi, Hu, Tao, Wang, Teng, Wu, Yufeng, Yu, Aobo, Chu, Jianan, Zhang, Han, Xiao, Hong, Peng, Wei, Di, Zengfeng, Qiao, Shan, and Mu, Gang
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
Two-dimensional (2D) superconductors supply important platforms for exploring new quantum physics and high-$T_c$ superconductivity. The intrinsic superconducting properties in the 2D iron-arsenic superconductors are still unknown owing to the difficulties in the preparation of ultrathin samples. Here we report the fabrication and physical investigations of the high quality single-crystalline ultrathin films of the iron-arsenic superconductor KCa$_2$Fe$_4$As$_4$F$_2$. For the sample with the thickness of 2.6$\sim$5 nm (1$\sim$2 unit cells), a sharp superconducting transition at around 30 K (onset point) is observed. Compare with the bulk material, the ultrathin sample reveals a relatively lower $T_c$, wider transition width, and broader flux liquid region under the in-plane field. Moreover, the angle dependent upper critical field follows the Tinkham model, demonstrating the two-dimensional superconductivity in ultrathin KCa$_2$Fe$_4$As$_4$F$_2$., Comment: 5 pages, 4 figures
- Published
- 2020
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