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)
a School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; b Zibo Vocational Institute, Shandong 255001, China
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.
Received: 26 September 2008
Revised: 17 November 2008
Accepted manuscript online:
PACS:
81.40.Jj
(Elasticity and anelasticity, stress-strain relations)
Fund: 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
Cite this article:
Liu Na-Na(刘娜娜), Song Ren-Bo(宋仁伯), and Du Da-Wei(杜大伟) Elastic constants and thermodynamic properties of Mg2SixSn1-x from first-principles calculations 2009 Chin. Phys. B 18 1979
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