Superconductivity in monolayer transition metal dichalcogenides is characterized by Ising-type pairing induced via a strong Zeeman-type spin–orbit coupling. When two transition metal dichalcogenides layers are coupled, more exotic superconducting phases emerge, which depend on the ratio of Ising-type protection and interlayer coupling strength. Here, we induce superconductivity in suspended MoS2 bilayers and unveil a coupled superconducting state with strong Ising-type spin–orbit coupling. Gating the bilayer symmetrically from both sides by ionic liquid gating varies the interlayer interaction and accesses electronic states with broken local inversion symmetry while maintaining the global inversion symmetry. We observe a strong suppression of the Ising protection that evidences a coupled superconducting state. The symmetric gating scheme not only induces superconductivity in both atomic sheets but also controls the Josephson coupling between the layers, which gives rise to a dimensional crossover in the bilayer.
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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
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J.T.Y. acknowledges funding from the European Research Council (consolidator grant no. 648855, Ig-QPD). We acknowledge D.-H. Xu for a fruitful discussion on the KLB model.
The authors declare no competing interests.
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Zheliuk, O., Lu, J.M., Chen, Q.H. et al. Josephson coupled Ising pairing induced in suspended MoS2 bilayers by double-side ionic gating. Nat. Nanotechnol. 14, 1123–1128 (2019) doi:10.1038/s41565-019-0564-1