Signature of Unconventional Superconductivity in a Copper-based Metal-Organic Framework with Perfect Kagome Structure

T. Takenaka; K. Ishihara; Y. Miao; X. Huang; W. Xu; D. Zhu; N. Su; J. -G. Cheng; T. Shibauchi

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arXiv · 1810.00569

Signature of Unconventional Superconductivity in a Copper-based Metal-Organic Framework with Perfect Kagome Structure

T. Takenaka·K. Ishihara·Y. Miao·X. Huang·W. Xu·D. Zhu·N. Su·J. -G. Cheng·T. Shibauchi

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Abstract

Recently, the superconductivity in a metal-organic framework (MOF) has been discovered for the first time in copper(II) benzenehexathiolate ([Cu$_3$(C$_6$S$_6$)]$_n$, Cu-BHT). The Cu atoms form a two-dimensional perfect Kagome lattice, which has the potential to host a metallic quantum spin liquid state. Here we present high-precision measurements of in-plane magnetic penetration depth $\lambda$ in Cu-BHT films down to 40\,mK. The temperature dependence of $\lambda$ shows a non-exponential, quasi-linear behavior at low temperatures, suggesting that unconventional superconductivity with low-energy quasiparticle excitations is realized in this system. With the reported non-Fermi liquid behavior, this finding implies that MOFs can provide a flexible platform to investigate the superconducting pairing mechanisms in the presence of spin frustration and strong quantum fluctuations.

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T. Takenaka, K. Ishihara, Y. Miao, X. Huang, W. Xu, D. Zhu, N. Su, J. -G. Cheng, T. Shibauchi. 2018-10-01. Signature of Unconventional Superconductivity in a Copper-based Metal-Organic Framework with Perfect Kagome Structure. https://arxiv.org/abs/1810.00569

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