中国物理B ›› 2021, Vol. 30 ›› Issue (1): 17102-.doi: 10.1088/1674-1056/abb667

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  • 收稿日期:2020-07-30 修回日期:2020-08-27 接受日期:2020-09-09 出版日期:2020-12-17 发布日期:2021-01-04

Structure prediction, electronic, and mechanical properties of alkali metal MB12 ( M= Be, Mg, Ca, Sr) from first principles

Chun-Ying Pu(濮春英)1, Rong-Mei Yu(于荣梅)1, Ting Wang(王婷)2, Zhen-Yan Xüe(薛振彦)1, Yong-Sheng Zhu(朱永胜)1, and Da-Wei Zhou(周大伟)1,†   

  1. 1 College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China; 2 Department of Mathematics and Statistics, Nanyang Normal University, Nanyang 473061, China
  • Received:2020-07-30 Revised:2020-08-27 Accepted:2020-09-09 Online:2020-12-17 Published:2021-01-04
  • Contact: †Corresponding author. E-mail: zhoudawei@nynu.edu.cn
  • Supported by:
    Projected supported by the National Natural Science Foundation of China (Grant Nos. U1904179, U1904178, and 51501093), the Key Science Fund of Educational Department of Henan Province, China (Grant Nos. 19A140013 and 20B140010), and the Science Technology Innovation Talents Fund in Universities of Henan Province, China (Grant No. 19HASTIT019).

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Abstract: Using the particle swarm optimization algorithm on structural search methods, we focus our crystal structures search on boron-rich alkali metal compounds of MB12 (M= Be, Mg, Ca, Sr) with simulation cell sizes of 1-2 formula units (f.u.) at 0 GPa. The structure, electronic, and mechanical properties of MB12 are obtained from the density functional theory using the plane-wave pseudopotential method within the generalized gradient approximations. The formation enthalpies of MB12 regarding to solid metal M and solid alpha-boron suggested the predicted structures can be synthesized except for BeB12. The calculated band structures show MB12 (M= Be, Mg, Ca, Sr) are all indirect semiconductors. All the calculated elastic constants of MB12 satisfy the the mechanical stable conditions. The mechanical parameters (i.e., bulk modulus, shear modulus, and Young's modulus) are derived using the Voigt-Reuss-Hill method. The G/B ratios indicated that the MB12 should exhibit brittle behavior. In addition, the hardness, Debye temperature, universal anisotropic index, and the percentage of anisotropy in compression and shear are also discussed in detail. We hope our results can inspire further experimental study on these boron-rich alkali-metal compounds.

Key words: first-principles calculations, structure searching, mechanical properties, boron-rich alkali-metal compounds

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

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81.40.Jj (Elasticity and anelasticity, stress-strain relations)