Yang Qiuping, Zhao Kaixuan, Liu Hanyu, Zhang Shoutao
Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China.
International Center for Computational Method & Software and State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China.
J Phys Chem Lett. 2021 Jul 1;12(25):5850-5856. doi: 10.1021/acs.jpclett.1c01096. Epub 2021 Jun 17.
The design of metal-bearing carbon-based materials with unique structures and intriguing properties is highly desirable in the fields of physics, chemistry, and materials science. Here, within swarm-intelligence structure search and first-principles computations, we uncovered several hitherto unknown sodium carbides (i.e., NaC, NaC, NaC, NaC, and NaC) under high pressure. Intriguingly, the C atom arrangement reveals multiple structure evolution behavior with increased carbon content, from isolated anions in NaC, tetramers in NaC, extended chains in NaC, pentagonal rings in NaC, to eventually hexagonal rings in NaC. Among predicted phases, the superconducting critical temperature of NaC could approach ∼42 K at 80 GPa, which is slightly higher than the of 39 K in the highest phonon-mediated superconductivity of MgB at ambient pressure. This work offers insights into the reaction of carbides containing alkali metals and paves the way for the future investigation of high superconductivity in metal carbide systems.
设计具有独特结构和有趣性质的含金属碳基材料在物理、化学和材料科学领域具有很高的需求。在此，通过群体智能结构搜索和第一性原理计算，我们在高压下发现了几种迄今为止未知的碳化钠（即NaC、NaC、NaC、NaC和NaC）。有趣的是，随着碳含量的增加，C原子排列呈现出多种结构演化行为，从NaC中的孤立阴离子、NaC中的四聚体、NaC中的延伸链、NaC中的五角环，到最终NaC中的六角环。在预测的相中，NaC的超导临界温度在80 GPa时可能接近42 K，略高于常压下MgB最高声子介导超导性的39 K。这项工作为含碱金属碳化物的反应提供了见解，并为未来研究金属碳化物系统中的高超导性铺平了道路。
