Surperhard monoclinic BC6N allotropes:First-principles investigations

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

作者机构：Key Laboratory of Applied ChemistryYanshan UniversityQinhuangdao 066004China Center for High Pressure Science and Technology Advanced ResearchBeijing 100094China 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2019年第28卷第9期

页      面：303-310页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

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

主　　题：superhard materials elastic properties boron-carbon-nitride ideal strength 

摘      要：Via structural searching methodology and first-principles calculations, we predicted two new BC6N allotropes, a Ccentered 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 *** 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 *** Cm-BC6N and Pm-BC6N are indirect semiconductors with band gaps of 2.66 eV and 0.36 eV, ***-BC6N exhibits the excellent ideal shear strength of 53.9 GPa in（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 *** Vickers hardness of Cm-BC6N is estimated to be above 80 GPa, which is more outstanding than those of t-BC6N and r-BC6N.