Wong C H, Lortz R, Buntov E A, Kasimova R E, Zatsepin A F
Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia.
Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Sci Rep. 2017 Nov 17;7(1):15815. doi: 10.1038/s41598-017-16038-5.
High temperature superconductivity does not necessarily require correlated electron systems with complex competing or coexisting orders. Instead, it may be achieved in a phonon-mediated classical superconductor having a high Debye temperature and large electronic density of states at the Fermi level in a material with light atoms and strong covalent bonds. Quasi-1D conductors seem promising due to the Van Hove singularities in their electronic density of states. In this sense, quasi-1D carbon structures are good candidates. In thin carbon nanotubes, superconductivity at ~15 K has been reported, and it is likely the strong curvature of the graphene sheet which enhances the electron-phonon coupling. We use an ab-initio approach to optimize superconducting quasi-1D carbon structures. We start by calculating a T of 13.9 K for (4.2) carbon nanotubes (CNT) that agrees well with experiments. Then we reduce the CNT to a ring, open the ring to form chains, optimize bond length and kink structure, and finally form a new type of carbon ring that reaches a T value of 115 K.
高温超导并不一定需要具有复杂竞争或共存有序态的关联电子系统。相反，在具有高德拜温度且在费米能级处具有大电子态密度的声子介导的经典超导体中，通过具有轻原子和强共价键的材料有可能实现高温超导。由于其电子态密度中的范霍夫奇点，准一维导体似乎很有前景。从这个意义上说，准一维碳结构是很好的候选材料。在细碳纳米管中，已报道了约15K的超导性，很可能是石墨烯片的强曲率增强了电子 - 声子耦合。我们使用从头算方法来优化超导准一维碳结构。我们首先计算出（4,2）碳纳米管的超导转变温度为13.9K，这与实验结果吻合得很好。然后我们将碳纳米管简化为一个环，打开环形成链，优化键长和扭结结构，最后形成一种新型碳环，其超导转变温度达到115K。
