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论文类型：期刊论文

发表时间：2017-09-07

发表刊物：JOURNAL OF APPLIED PHYSICS

收录刊物：Scopus、SCIE、EI

卷号：122

期号：9

ISSN号：0021-8979

摘要：Employing density functional theory calculations, mechanical and electronic properties of stable penta-B2N4 and penta-B3N3 monolayers are investigated. The different mechanical parameters obtained along different tensile directions suggest both the penta-B2N4 and penta-B3N3 demonstrate mechanical anisotropy. Moreover, due to the lower space group symmetry of penta-B3N3, its anisotropy is more prominent than that of the penta-B2N4. It was found that both the penta-B2N4 and penta-B3N3 are fast to fracture along the direction R-1 due to the small fracture strain, but hard to be stretched because of the large Young's modulus. Generally, penta-B2N4 shows better mechanical properties than those of penta-B3N3 in terms of Young's modulus and intrinsic strength. Besides, under the tensile strain, penta-B2N4 keeps its metallicity, but the band gap of penta-B3N3 can be effectively tailored, even inducing a transition from the direct to indirect band gap or transition from the semiconductor to metal. Further analysis of partial charge densities indicates breaking of B-N bonds is the main cause for the band gap enlargement, and similarly, formation of B-N bonds is the reason for the semiconductor-to-metal transition of penta-B3N3. Published by AIP Publishing.