中国物理B ›› 2011, Vol. 20 ›› Issue (3): 37101-037101.doi: 10.1088/1674-1056/20/3/037101

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First-principles study of electronic properties and stability of Nb5SiB2 (001) surface

王福合1, 许昱江子2, 尚家香2   

  1. (1)Department of Physics, Capital Normal University, Beijing 100048, China; (2)Key Laboratory of Aerospace Materials and Performance (Ministry of Educatio14), School of Materials Science and Engineering, Beihang University, Beijing 100191, China
  • 收稿日期:2010-10-04 修回日期:2010-10-25 出版日期:2011-03-15 发布日期:2011-03-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 50771004).

First-principles study of electronic properties and stability of Nb5SiB2 (001) surface

Xu Yu-Jiang-Zi(许昱江子)a), Shang Jia-Xiang(尚家香)a),and Wang Fu-He(王福合)b)   

  1. a Key Laboratory of Aerospace Materials and Performance (Ministry of Educatio14), School of Materials Science and Engineering, Beihang University, Beijing 100191, China; b Department of Physics, Capital Normal University, Beijing 100048, China
  • Received:2010-10-04 Revised:2010-10-25 Online:2011-03-15 Published:2011-03-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 50771004).

摘要: The density functional calculations are performed to study the electronic structure and stability of Nb5SiB2 (001) surface with different terminations. The calculated cleavage energies along the (001) planes in Nb5SiB2 are 5.015 ·m-2 and 6.593 J·m-2 with the break of Nb--Si and Nb--NbB bonds, respectively. There exists a close correlation between the surface relaxation including surface ripple and the cleavage energy: the larger the cleavage energy, the larger the surface relaxation. Moreover, the surface stability of the Nb5SiB2 (001) with different terminations has been investigated by the chemical potential phase diagram. From a thermodynamics point of view, the four terminations can be stabilized under different conditions. In chemical potential space, NbB (Nb) and Nb (Si) terminations are just stable in a small area, whereas Si (Nb) and Nb (NbB) terminations are stable in a large area (the letters in brackets represent the subsurface atoms).

关键词: first principles, Nb5SiB2 surface, electronic properties, surface stability

Abstract: The density functional calculations are performed to study the electronic structure and stability of Nb5SiB2 (001) surface with different terminations. The calculated cleavage energies along the (001) planes in Nb5SiB2 are 5.015 ·m-2 and 6.593 J·m-2 with the break of Nb–Si and Nb–NbB bonds, respectively. There exists a close correlation between the surface relaxation including surface ripple and the cleavage energy: the larger the cleavage energy, the larger the surface relaxation. Moreover, the surface stability of the Nb5SiB2 (001) with different terminations has been investigated by the chemical potential phase diagram. From a thermodynamics point of view, the four terminations can be stabilized under different conditions. In chemical potential space, NbB (Nb) and Nb (Si) terminations are just stable in a small area, whereas Si (Nb) and Nb (NbB) terminations are stable in a large area (the letters in brackets represent the subsurface atoms).

Key words: first principles, Nb5SiB2 surface, electronic properties, surface stability

中图分类号:  (Total energy and cohesive energy calculations)

  • 71.15.Nc
73.20.At (Surface states, band structure, electron density of states)