"Gate-Induced Interfacial Superconductivity in 1T-SnSe2"

Junwen Zeng: Erfu Liu, Yajun Fu, Zhuoyu Chen, Chen Pan, Chenyu Wang, Miao Wang, Yaojia Wang, Kang Xu, Songhua Cai, Xingxu Yan, Yu Wang, Xiaowei Liu, Peng Wang, Shi-Jun Liang, Yi Cui, Harold Y. Hwang, Hongtao Yuan, and Feng Miao; Nano Letters, 02/14/18.

Additional Authors: Erfu Liu, Yajun Fu, Zhuoyu Chen, Chen Pan, Chenyu Wang, Miao Wang, Yaojia Wang, Kang Xu, Songhua Cai, Xingxu Yan, Yu Wang, Xiaowei Liu, Peng Wang, Shi-Jun Liang, Yi Cui, Harold Y. Hwang, Hongtao Yuan, and Feng Miao

Abstract:

Layered metal chalcogenide materials provide a versatile platform to investigate emergent phenomena and two-dimensional (2D) superconductivity at/near the atomically thin limit. In particular, gate-induced interfacial superconductivity realized by the use of an electric-double-layer transistor (EDLT) has greatly extended the capability to electrically induce superconductivity in oxides, nitrides, and transition metal chalcogenides and enable one to explore new physics, such as the Ising pairing mechanism. Exploiting gate-induced superconductivity in various materials can provide us with additional platforms to understand emergent interfacial superconductivity. Here, we report the discovery of gate-induced 2D superconductivity in layered 1T-SnSe2, a typical member of the main-group metal dichalcogenide (MDC) family, using an EDLT gating geometry. A superconducting transition temperature Tc ≈ 3.9 K was demonstrated at the EDL interface. The 2D nature of the superconductivity therein was further confirmed based on (1) a 2D Tinkham description of the angle-dependent upper critical field Bc2, (2) the existence of a quantum creep state as well as a large ratio of the coherence length to the thickness of superconductivity. Interestingly, the in-plane Bc2 approaching zero temperature was found to be 2–3 times higher than the Pauli limit, which might be related to an electric field-modulated spin–orbit interaction. Such results provide a new perspective to expand the material matrix available for gate-induced 2D superconductivity and the fundamental understanding of interfacial superconductivity.