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 around 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, 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 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.
@article{arxiv.1802.00900,
title = {Gate-Induced Interfacial Superconductivity in 1T-SnSe2},
author = {Junwen Zeng and Erfu Liu and Yajun Fu and Zhuoyu Chen and Chen Pan and Chenyu Wang and Miao Wang and Yaojia Wang and Kang Xu and Songhua Cai and Xingxu Yan and Yu Wang and Xiaowei Liu and Peng Wang and Shi-Jun Liang and Yi Cui and Harold Y. Hwang and Hongtao Yuan and Feng Miao},
journal= {arXiv preprint arXiv:1802.00900},
year = {2018}
}