中国物理B ›› 2009, Vol. 18 ›› Issue (5): 1979-1984.doi: 10.1088/1674-1056/18/5/041

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Elastic constants and thermodynamic properties of Mg2SixSn1-x from first-principles calculations

宋仁伯1, 杜大伟1, 刘娜娜2   

  1. (1)School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; (2)School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;Zibo Vocational Institute, Shandong 255001, China
  • 收稿日期:2008-09-26 修回日期:2008-11-17 出版日期:2009-05-20 发布日期:2009-05-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 50504002), China Postdoctoral Science Foundation (Grant No 20060390030) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Mini

Elastic constants and thermodynamic properties of Mg2SixSn1-x from first-principles calculations

Liu Na-Na(刘娜娜)a)b)†, Song Ren-Bo(宋仁伯)a), and Du Da-Wei(杜大伟)a)   

  1. a School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; b Zibo Vocational Institute, Shandong 255001, China
  • Received:2008-09-26 Revised:2008-11-17 Online:2009-05-20 Published:2009-05-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 50504002), China Postdoctoral Science Foundation (Grant No 20060390030) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Mini

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摘要： This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x (x=0, 0.25, 0.5, 0.75, 1) compounds by first-principles total energy calculations using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation for the exchange and correlation potential. The elastic constants of Mg2SixSn1-x were calculated. It shows that, at 273 K, the elastic constants of Mg2Si and Mg2Sn are well consistent with previous experimental data. The isotropy decreases with increasing Sn content. The dependences of the elastic constants, the bulk modulus, the shear modulus and the Debye temperatures of Mg2Si and Mg2Si_{0.5}Sn_{0.5} on pressure were discussed. Through the quasi-harmonic Debye model, in which phononic effects were considered, the specific heat capacities of Mg2SixSn1-x at constant volume and constant pressure were calculated. The calculated specific heat capacities are well consistent with the previous experimental data.

关键词: first-principles, Mg2SixSn1-x, elastic constants, heat capacity

Abstract: This paper stuides the elastic constants and some thermodynamic properties of Mg2SixSn1-x (x=0, 0.25, 0.5, 0.75, 1) compounds by first-principles total energy calculations using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation for the exchange and correlation potential. The elastic constants of Mg2SixSn1-x were calculated. It shows that, at 273 K, the elastic constants of Mg2Si and Mg2Sn are well consistent with previous experimental data. The isotropy decreases with increasing Sn content. The dependences of the elastic constants, the bulk modulus, the shear modulus and the Debye temperatures of Mg2Si and Mg2Si$_{0.5}$Sn$_{0.5}$ on pressure were discussed. Through the quasi-harmonic Debye model, in which phononic effects were considered, the specific heat capacities of Mg2SixSn1-x at constant volume and constant pressure were calculated. The calculated specific heat capacities are well consistent with the previous experimental data.

Key words: first-principles, Mg2SixSn1-x, elastic constants, heat capacity

中图分类号:  (Elasticity and anelasticity, stress-strain relations)

  • 81.40.Jj
62.20.D- (Elasticity) 65.40.G- (Other thermodynamical quantities) 63.70.+h (Statistical mechanics of lattice vibrations and displacive phase transitions) 63.20.-e (Phonons in crystal lattices) 65.40.Ba (Heat capacity)