Center for Applied Physics and Technology, Department of Materials Science and Engineering, HEDPS, BKL-MEMD, College of Engineering, Peking University, Beijing 100871, China.
Institute of Mineral Engineering, Division of Materials Science and Engineering, RWTH Aachen University, 52064 Aachen, Germany.
Nanoscale. 2018 Mar 29;10(13):6099-6104. doi: 10.1039/C8NR00110C.
A new two-dimensional (2D) carbon allotrope, Hexa-C20, composed of C20 fullerene is proposed. State-of-the-art first principles calculations combined with solving the linearized phonon Boltzmann transport equation confirm that the new carbon structure is not only dynamically and thermally stable, but also can withstand temperatures as high as 1500 K. Hexa-C20 possesses a quasi-direct band gap of 3.28 eV, close to that of bulk ZnO and GaN. The intrinsic lattice thermal conductivity κlat of Hexa-C20 is 1132 W m-1 K-1 at room temperature, which is much larger than those of most carbon materials such as graphyne (82.3 W m-1 K-1) and penta-graphene (533 W m-1 K-1). Further analysis of its phonons uncovers that the main contribution to κlat is from the three-phonon scattering, while the three acoustic branches are the main heat carriers, and strongly coupled with optical phonon branches via an absorption process. The ultrahigh lattice thermal conductivity and an intrinsic wide band gap make the Hexa-C20 sheet attractive for potential thermal management applications.
一种由 C20 富勒烯组成的新型二维（2D）碳同素异形体 Hexa-C20 被提出。最先进的第一性原理计算结合线性化声子玻尔兹曼输运方程的求解，证实了新的碳结构不仅在动力学和热力学上是稳定的，而且可以承受高达 1500 K 的温度。Hexa-C20 具有准直接带隙为 3.28 eV，接近体相 ZnO 和 GaN。室温下，Hexa-C20 的本征晶格热导率 κlat 为 1132 W m-1 K-1，远大于大多数碳材料，如炔烃（82.3 W m-1 K-1）和五石墨烯（533 W m-1 K-1）。对其声子的进一步分析表明，κlat 的主要贡献来自于三声子散射，而三个声学支是主要的热载体，并通过吸收过程与光学声子支强烈耦合。超高的晶格热导率和本征宽带隙使得 Hexa-C20 片在潜在的热管理应用中具有吸引力。
