中国物理B ›› 2019, Vol. 28 ›› Issue (9): 96201-096201.doi: 10.1088/1674-1056/ab3439

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Surperhard monoclinic BC6N allotropes: First-principles investigations

Nian-Rui Qu(屈年瑞), Hong-Chao Wang(王洪超), Qing Li(李青), Yi-Ding Li(李一鼎), Zhi-Ping Li(李志平), Hui-Yang Gou(缑慧阳), Fa-Ming Gao(高发明)   

  1. 1 Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004, China;
    2 Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
  • 收稿日期:2019-06-17 修回日期:2019-07-10 出版日期:2019-09-05 发布日期:2019-09-05
  • 通讯作者: Zhi-Ping Li, Fa-Ming Gao E-mail:zpli@ysu.edu.cn;fmgao@ysu.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 21671168 and 21875205), the Hebei Natural Science Foundation, China (Grant No. B2015203096), and the Qinhuangdao Science and Technology Support Program, China (Grant No. 201703A014).

Surperhard monoclinic BC6N allotropes: First-principles investigations

Nian-Rui Qu(屈年瑞)1, Hong-Chao Wang(王洪超)1, Qing Li(李青)1, Yi-Ding Li(李一鼎)1, Zhi-Ping Li(李志平)1, Hui-Yang Gou(缑慧阳)2, Fa-Ming Gao(高发明)1   

  1. 1 Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004, China;
    2 Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
  • Received:2019-06-17 Revised:2019-07-10 Online:2019-09-05 Published:2019-09-05
  • Contact: Zhi-Ping Li, Fa-Ming Gao E-mail:zpli@ysu.edu.cn;fmgao@ysu.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 21671168 and 21875205), the Hebei Natural Science Foundation, China (Grant No. B2015203096), and the Qinhuangdao Science and Technology Support Program, China (Grant No. 201703A014).

摘要:

Via structural searching methodology and first-principles calculations, we predicted two new BC6N allotropes, a C-centered monoclinic BC6N (Cm-BC6N) and a primitive-centered monoclinic BC6N (Pm-BC6N). The lattice vibrations, elastic properties, ideal strength, theoretical hardness, and electronic structure of the predicted BC6N were investigated systematically. Our results reveal that Cm-BC6N is more favorable energetically than graphite-like g-BC6N above 20.6 GPa, which is lower than the transition pressures of r-BC6N, t-BC6N, and Pm-BC6N. Both Cm-BC6N and Pm-BC6N are indirect semiconductors with band gaps of 2.66 eV and 0.36 eV, respectively. Cm-BC6N exhibits the excellent ideal shear strength of 53.9 GPa in (011)[011], much greater than that of Pm-BC6N (25.0 GPa in (010)[101] shear direction), and Cm-BC6N shows a much lower anisotropy in shear strength than Pm-BC6N. The Vickers hardness of Cm-BC6N is estimated to be above 80 GPa, which is more outstanding than those of t-BC6N and r-BC6N.

关键词: superhard materials, elastic properties, boron-carbon-nitride, ideal strength

Abstract:

Via structural searching methodology and first-principles calculations, we predicted two new BC6N allotropes, a C-centered monoclinic BC6N (Cm-BC6N) and a primitive-centered monoclinic BC6N (Pm-BC6N). The lattice vibrations, elastic properties, ideal strength, theoretical hardness, and electronic structure of the predicted BC6N were investigated systematically. Our results reveal that Cm-BC6N is more favorable energetically than graphite-like g-BC6N above 20.6 GPa, which is lower than the transition pressures of r-BC6N, t-BC6N, and Pm-BC6N. Both Cm-BC6N and Pm-BC6N are indirect semiconductors with band gaps of 2.66 eV and 0.36 eV, respectively. Cm-BC6N exhibits the excellent ideal shear strength of 53.9 GPa in (011)[011], much greater than that of Pm-BC6N (25.0 GPa in (010)[101] shear direction), and Cm-BC6N shows a much lower anisotropy in shear strength than Pm-BC6N. The Vickers hardness of Cm-BC6N is estimated to be above 80 GPa, which is more outstanding than those of t-BC6N and r-BC6N.

Key words: superhard materials, elastic properties, boron-carbon-nitride, ideal strength

中图分类号:  (Mechanical properties of solids)

  • 62.20.-x