摘要
以二十面体为基元的富硼化合物具有复杂多样的电子和机械性能.在本工作中,我们采用粒子群优化结构预测方法结合第一性原理计算,首次对二十面体基元的三元B_(12)CN和B_(13)CN化合物的晶体结构和性质进行了全面系统的研究.我们搜索得到了B_(13)CN和B_(12)CN化合物的新结构,其空间群均为Cmc21,与α-B的变体结构相比,新结构具有更优异的热力学稳定性.B_(12)CN的热力学稳定性和机械性能均稍逊于B_(13)CN.此外,B含量的微小差异造成了B_(12)CN与B_(13)CN两种三元化合物迥异的电学特性,即B_(13)CN具有半导体特性,而B_(12)CN具有空穴型导电特性.此外,在B_(12)CN与B_(13)CN系列新结构的拉伸过程中,由于二十面体的连续破坏和二十面体之间的连续断键造成的应力再增强、结构多级破坏和类蠕变变形等特殊变形机制也同样被揭示.
Boron-rich compounds with icosahedral-based structures possess rich,fascinating electronic and mechanical properties.Herein,the first comprehensive and systematic study of the crystal structures and properties of ternary B_(12)CN and B_(13)CN compounds with icosahedral structures has been performed by using particle swarm optimized structure pre-diction methods in combination with first-principles calcula-tions.Compared with the widely studied variant structure ofα-boron,the newly discovered Cmc21 structures are thermo-dynamically more stable for B_(12)CN and B_(13)CN.For structures with the same space group,B_(13)CN possesses superior ther-modynamic stability and mechanical properties than B_(12)CN.Electronic structure calculations indicate that the boron-rich B-C-N system has abundant and tunable electronic proper-ties,i.e.,B_(13)CN is a semiconductor,and B_(12)CN possesses a hole-type conducting characteristic.The systematic study of structural ideal tensile strength indicates successive damage to icosahedra and successive bond breaks between icosahedra during tensile processes,leading to interesting deformation mechanisms,such as stress re-enhancement,structural mul-tistep damage,and creep-like deformation.
作者
朱莉
马梦冬
熊美
高琦
武英举
应盼
魏旭东
赵智胜
辛圣炜
何巨龙
田永君
Li Zhu;Mengdong Ma;Mei Xiong;Qi Gao;Yingju Wu;Pan Ying;Xudong Wei;Zhisheng Zhao;Shengwei Xin;Julong He;Yongjun Tian(Center for High Pressure Science(CHiPS),State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China;Macao Institute of Materials Science and Engineering,Macao University of Science and Technology,Taipa 999078,Macao SAR,China;National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die&Mould,Tianjin University of Technology and Education,Tianjin 300222,China;Key Laboratory for Microstructural Material Physics of Hebei Province,School of Science,Yanshan University,Qinhuangdao 066004,China;Clean Nano Energy Center,State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China)
基金
supported by the National Key R&D Program of China(2018YFA0703400)
the National Natural Science Foundation of China(52073245,52002118,52202071,52202049)
Macao Youth Scholars Program(AM2021015)
the Postdoctoral Science Preferential Funding of Hebei Province(B2022003021,B2021005001)。
