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arXiv · 1903.07627

Type-II Ising Pairing in Few-Layer Stanene

Joseph Falson·Yong Xu·Menghan Liao·Yunyi Zang·Kejing Zhu·Chong Wang·Zetao Zhang·Hongchao Liu·Wenhui Duan·Ke He·Haiwen Liu·Jurgen H. Smet·Ding Zhang·Qi-Kun Xue
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Abstract

Spin-orbit coupling has proven indispensable in realizing topological materials and more recently Ising pairing in two-dimensional superconductors. This pairing mechanism relies on inversion symmetry breaking and sustains anomalously large in-plane polarizing magnetic fields whose upper limit is expected to diverge at low temperatures, although experimental demonstration of this has remained elusive due to the required fields. In this work, the recently discovered superconductor few-layer stanene, i.e. epitaxially strained $\alpha$-Sn, is shown to exhibit a new type of Ising pairing between carriers residing in bands with different orbital indices near the $\Gamma$-point. The bands are split as a result of spin-orbit locking without the participation of inversion symmetry breaking. The in-plane upper critical field is strongly enhanced at ultra-low temperature and reveals the sought for upturn.

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Joseph Falson, Yong Xu, Menghan Liao, Yunyi Zang, Kejing Zhu, Chong Wang, Zetao Zhang, Hongchao Liu, Wenhui Duan, Ke He, Haiwen Liu, Jurgen H. Smet, Ding Zhang, Qi-Kun Xue. 2019-03-18. Type-II Ising Pairing in Few-Layer Stanene. https://doi.org/10.1126/science.aax3873

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