Quantum Transport in 2D Superconducting NbSe₂

Jun-Sheng Wu^1,2*, Kuan-Lin Chen^1,2, Yu-Chiang Hsieh^1,2, Kuo-En Chang^1,2, Chiu-Hau Huang^1,2, Ching-Hua Kao^1,2, Tse-Ming Chen^1,2

¹Department of Physics, National Cheng Kung University, Tainan, Taiwan
²Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, Taiwan

* Presenter:Jun-Sheng Wu, email:jswu@phys.ncku.edu.tw

Superconducting devices, such as Josephson junction or superconducting quantum interference device (SQUID), are important components to build up today’s technology owing to the unique characteristics which are unavailable in semiconductor devices. The discovery of van der Waals superconductors, like NbSe₂^[1], bears consequences for both fundamental physics and device applications due to its distinctive physics and easiness to engineer towards two-dimensional (2D) electronics^[2-4]. Here, we study the quantum transport and superconducting phase transition in few-layer NbSe₂. At zero magnetic field, we observed a two-step transition following an unusual large critical current. The transitions at different magnetic field and temperature are also measured and have nonlinear responses. We attribute these behaviors to the vortex pinning and the mixing of different pairing symmetries in 2D NbSe₂^[5]. Our results may pave the way to unveil the mystery of 2D superconductors and lead to new applications in superconducting electronic devices.

Reference
1. X. Xi et al., Nature Physics 12, 139-143 (2016).
2. A. Tsen et al., Nature Physics 12, 208-212 (2016).
3. A. Benyamini et al., Nature Physics 15, 947-953 (2019).
4. A. Wieteska et al., arXiv preprint arXiv:1903.05253, (2019).
5. A. Hamill et al., Nature Physics, 1-6 (2021).

Keywords: 2D superconductors, NbSe₂, vortex pinning, pairing symmetry