Superconductivity in a layered cobalt oxychalcogenide Na$_{2}$CoSe$_{2}$O with a triangular lattice
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| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866913285659426816 |
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| author | Cheng, Jingwen Bai, Jianli Ruan, Binbin Liu, Pinyu Huang, Yu Dong, Qingxin Huang, Yifei Sun, Yingrui Li, Cundong Zhang, Libo Liu, Qiaoyu Zhu, Wenliang Ren, Zhian Chen, Genfu |
| author_facet | Cheng, Jingwen Bai, Jianli Ruan, Binbin Liu, Pinyu Huang, Yu Dong, Qingxin Huang, Yifei Sun, Yingrui Li, Cundong Zhang, Libo Liu, Qiaoyu Zhu, Wenliang Ren, Zhian Chen, Genfu |
| contents | Unconventional superconductivity in bulk materials under ambient pressure is extremely rare among the 3d transition metal compounds outside the layered cuprates and iron-based family. It is predominantly linked to highly anisotropic electronic properties and quasi-two-dimensional (2D) Fermi surfaces. To date, the only known example of a Co-based exotic superconductor is the hydrated layered cobaltate, Na$_{x}$CoO$_{2}\cdot$ yH$_{2}$O, and its superconductivity is realized in the vicinity of a spin-1/2 Mott state. However, the nature of the superconductivity in these materials is still a subject of intense debate, and therefore, finding a new class of superconductors will help unravel the mysteries of their unconventional superconductivity. Here we report the discovery of superconductivity at $\sim$ 6.3 K in our newly synthesized layered compound Na$_{2}$CoSe$_{2}$O, in which the edge-shared CoSe$_{6}$ octahedra form [CoSe$_{2}$] layers with a perfect triangular lattice of Co ions. It is the first 3d transition metal oxychalcogenide superconductor with distinct structural and chemical characteristics. Despite its relatively low $T_{c}$, this material exhibits very high superconducting upper critical fields, $μ_{0}H_{c2}(0)$, which far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles calculations show that Na$_{2}$CoSe$_{2}$O is a rare example of a negative charge transfer superconductor. This cobalt oxychalcogenide with a geometrical frustration among Co spins shows great potential as a highly appealing candidate for the realization of unconventional and/or high-$T_{c}$ superconductivity beyond the well-established Cu- and Fe-based superconductor families and opens a new field in the physics and chemistry of low-dimensional superconductors. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2310_17464 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Superconductivity in a layered cobalt oxychalcogenide Na$_{2}$CoSe$_{2}$O with a triangular lattice Cheng, Jingwen Bai, Jianli Ruan, Binbin Liu, Pinyu Huang, Yu Dong, Qingxin Huang, Yifei Sun, Yingrui Li, Cundong Zhang, Libo Liu, Qiaoyu Zhu, Wenliang Ren, Zhian Chen, Genfu Superconductivity Materials Science Strongly Correlated Electrons Unconventional superconductivity in bulk materials under ambient pressure is extremely rare among the 3d transition metal compounds outside the layered cuprates and iron-based family. It is predominantly linked to highly anisotropic electronic properties and quasi-two-dimensional (2D) Fermi surfaces. To date, the only known example of a Co-based exotic superconductor is the hydrated layered cobaltate, Na$_{x}$CoO$_{2}\cdot$ yH$_{2}$O, and its superconductivity is realized in the vicinity of a spin-1/2 Mott state. However, the nature of the superconductivity in these materials is still a subject of intense debate, and therefore, finding a new class of superconductors will help unravel the mysteries of their unconventional superconductivity. Here we report the discovery of superconductivity at $\sim$ 6.3 K in our newly synthesized layered compound Na$_{2}$CoSe$_{2}$O, in which the edge-shared CoSe$_{6}$ octahedra form [CoSe$_{2}$] layers with a perfect triangular lattice of Co ions. It is the first 3d transition metal oxychalcogenide superconductor with distinct structural and chemical characteristics. Despite its relatively low $T_{c}$, this material exhibits very high superconducting upper critical fields, $μ_{0}H_{c2}(0)$, which far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles calculations show that Na$_{2}$CoSe$_{2}$O is a rare example of a negative charge transfer superconductor. This cobalt oxychalcogenide with a geometrical frustration among Co spins shows great potential as a highly appealing candidate for the realization of unconventional and/or high-$T_{c}$ superconductivity beyond the well-established Cu- and Fe-based superconductor families and opens a new field in the physics and chemistry of low-dimensional superconductors. |
| title | Superconductivity in a layered cobalt oxychalcogenide Na$_{2}$CoSe$_{2}$O with a triangular lattice |
| topic | Superconductivity Materials Science Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2310.17464 |