Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore, 560012, Karnataka, India.
Angew Chem Int Ed Engl. 2017 Aug 14;56(34):10093-10097. doi: 10.1002/anie.201610584. Epub 2017 Jan 27.
An electron-counting strategy starting from magnesium boride was used to show the inevitability of hexagonal holes in 2D borophene. The number (hole density, HD) and distribution of the hexagonal holes determine the binding energy per boron atom in monolayer borophenes. The relationship between binding energy and HD changes dramatically when the borophene is placed on a Ag(111) surface. The distribution of holes in borophenes on Ag(111) surfaces depends on the temperature. DFT calculations show that aside from the previously reported S1 and S2 borophene phases, other polymorphs may also be competitive. Plots of the electron density distribution of the boron sheets suggest that the observed STM image of an S2 phase corresponds to a sheet with a HD of 2/15 instead of a sheet with a HD of 1/5. The hole density and the hole distribution echo the distribution of vacancies and extra occupancies in complex β-rhombohedral boron.
采用电子计数策略从硼化镁出发，证明了二维硼烯中六方孔的必然性。六方孔的数量（空穴密度，HD）和分布决定了单层硼烯中每个硼原子的结合能。当硼烯置于 Ag(111)表面时，结合能与 HD 的关系会发生剧烈变化。Ag(111)表面上硼烯的空穴分布取决于温度。DFT 计算表明，除了之前报道的 S1 和 S2 硼烯相之外，其他多晶型相也可能具有竞争力。硼片电子密度分布的图表明，观察到的 S2 相的 STM 图像对应于 HD 为 2/15 的片，而不是 HD 为 1/5 的片。空穴密度和空穴分布与复杂β-菱形硼中空位和额外占据的分布相呼应。
