Metallization and softening of B₆O at high pressure

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• 作者：Yuehui Wang^a ; Yachun Wang^b ; Tiankai Yao^b ; Hui Li^b ; Lailei Wu^b ; Meng Yang^b ; Jingwu Zhang^b ; ^{ziw@ysu.edu.cn" class="auth_mail} ; Huiyang Gou^b ; ^{huiyang.gou@gmail.com" class="auth_mail}
• 关键词：B6O ; High-pressure phase ; Metallization and softening ; First-principles calculations
• 刊名：Journal of Alloys and Compounds
• 出版年：5 July, 2014
• 年：2014
• 卷：600
• 期：Complete
• 页码：71-77
• 全文大小：789 K

文摘

Structural stability, elastic and electronic properties of boron suboxide, B₆O, up to 300 GPa were investigated by first-principles calculations. Structural searching and enthalpy differences calculations identify a high-pressure phase for B₆O with monoclinic Cc structure (denoted as 尾-B₆O), which is energetically preferable to the known R-3 m-type phase above 245 GPa. 尾-B₆O phase forms a three-dimensional covalent network mainly composed of pentagonal pyramids and zig-zag O-B1-O chains extended along c-direction. 尾-B₆O phase is found to be stable examined by the calculated elastic constants and phonon dispersion and exhibits metallic behavior and greater elastic and hardness anisotropy, totally different from the semiconducting character and relative isotropy of ground state structure. Moreover, 尾-B₆O is predicted to soften significantly with a Vicker鈥檚 hardness of about 20.7 GPa.