Two-Dimensional Boron Monolayer Sheets

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• 作者：Xiaojun Wu ; Jun Dai ; Yu Zhao ; Zhiwen Zhuo ; Jinlong Yang ; Xiao Cheng Zeng
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：August 28, 2012
• 年：2012
• 卷：6
• 期：8
• 页码：7443-7453
• 全文大小：1100K
• 年卷期：v.6,no.8(August 28, 2012)
• ISSN：1936-086X

文摘

Boron, a nearest-neighbor of carbon, is possibly the second element that can possess free-standing flat monolayer structures, evidenced by recent successful synthesis of single-walled and multiwalled boron nanotubes (MWBNTs). From an extensive structural search using the first-principles particle-swarm optimization (PSO) global algorithm, two boron monolayers (伪₁- and 尾₁-sheet) are predicted to be the most stable 伪- and 尾-types of boron sheets, respectively. Both boron sheets possess greater cohesive energies than the state-of-the-art two-dimensional boron structures (by more than 60 meV/atom based on density functional theory calculation using PBE0 hybrid functional), that is, the 伪-sheet previously predicted by Tang and Ismail-Beigi and the g_1/8- and g_2/15-sheets (both belonging to the 尾-type) recently reported by Yakobson and co-workers. Moreover, the PBE0 calculation predicts that the 伪-sheet is a semiconductor, while the 伪₁-, 尾₁-, g_1/8-, and g_2/15-sheets are all metals. When two 伪₁ monolayers are stacked on top each other, the bilayer 伪₁-sheet remains flat with an optimal interlayer distance of 3.62 脜, which is close to the measured interlayer distance (3.2 脜) in MWBNTs.

Keywords:

boron monolayer sheet; hybrid density functional; interlayer distance; double-walled boron nanotube