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arXiv · 2411.12231

Two-dimensional superconductivity in new niobium dichalcogenides-based bulk superlattices

Kaibao Fan·Mengzhu Shi·Houpu Li·Ziji Xiang·Xianhui Chen
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Abstract

Transition metal dichalcogenides exhibit many unexpected properties including two-dimensional (2D) superconductivity as the interlayer coupling being weakened upon either layer-number reduction or chemical intercalation. Here we report the realization of 2D superconductivity in the newly-synthesized niobium dichalcogenides-based bulk superlattices Ba$_{0.75}$ClNbS$_{2}$ and Ba$_{0.75}$ClNbSe$_{2}$, which consists of the alternating stacking of monolayer $H$-NbS$_{2}$ (or $H$-NbSe$_{2}$) and monolayer inorganic insulator spacer Ba$_{0.75}$Cl. Magnetic susceptibility and resistivity measurements show that both superlattices belong to type-II superconductor with $T_{c}$ of 1 K and 1.25 K, respectively. Intrinsic 2D superconductivity is confirmed for both compounds below a Berezinskii-Kosterlitz-Thouless transition and a large anisotropy of the upper critical field. Furthermore, the upper critical field along $ab$ plane ($H_{c2}^{\parallel ab}$) exceeds the Pauli limit ($μ_{0}H_{p}$) in Ba$_{0.75}$ClNbSe$_{2}$, highlighting the influence of spin-orbit interactions. Our results establish a generic method for realizing the 2D superconducting properties in bulk superlattice materials.

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Kaibao Fan, Mengzhu Shi, Houpu Li, Ziji Xiang, Xianhui Chen. 2024-11-19. Two-dimensional superconductivity in new niobium dichalcogenides-based bulk superlattices. https://arxiv.org/abs/2411.12231

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