中国物理B ›› 2011, Vol. 20 ›› Issue (3): 30508-030508.doi: 10.1088/1674-1056/20/3/030508

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Phase transition, structural and thermodynamic properties of Mg2Si polymorphs

余本海, 陈东   

  1. College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China
  • 收稿日期:2010-08-14 修回日期:2010-09-16 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 Nos. 11005088 and 11047186), the Basic and Advanced Technology of Henan Province, China (Grant No. 102300410241), and the Science and Technology of Henan Province, China (Grant N

Phase transition, structural and thermodynamic properties of Mg2Si polymorphs

Yu Ben-Hai(余本海) and Chen Dong(陈东)†   

  1. College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China
  • Received:2010-08-14 Revised:2010-09-16 Online:2011-03-15 Published:2011-03-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11005088 and 11047186), the Basic and Advanced Technology of Henan Province, China (Grant No. 102300410241), and the Science and Technology of Henan Province, China (Grant No. 082300410050).

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摘要： The plane-wave pseudo-potential method within the framework of first principles is used to investigate the structural and elastic properties of Mg2Si in its intermediate pressure (Pnma) and high pressure phases (P63/mmc). The lattice constants, the band structures. The bulk moduli of the Mg2Si polymorphs are presented and discussed. The phase transition from anti-cotunnite to Ni2In-type Mg2Si is successfully reproduced using a vibrational Debye-like model. The phase boundary can be described as P=24.02994+3.93×10-3T-4.66816×10-5T2-2.2501×10-9T3+2.33786×1011T4. To complete the fundamental characteristics of these polymorphs we have analysed thermodynamic properties, such as thermal expansion and heat capacity, in a pressure range of 0--40 GPa and a temperature range of 0--1300 K. The obtained results tend to support the available experimental data and other theoretical results. Therefore, the present results indicate that the combination of first principles and a vibrational Debye-like model is an efficient scheme to simulate the high temperature behaviours of Mg2Si.

关键词: semiconductors, thermodynamic properties, phase transition, band structure

Abstract: The plane-wave pseudo-potential method within the framework of first principles is used to investigate the structural and elastic properties of Mg2Si in its intermediate pressure (Pnma) and high pressure phases (P63/mmc). The lattice constants, the band structures. The bulk moduli of the Mg2Si polymorphs are presented and discussed. The phase transition from anti-cotunnite to Ni2In-type Mg2Si is successfully reproduced using a vibrational Debye-like model. The phase boundary can be described as P=24.02994+3.93×10-3T-4.66816×10-5T2-2.2501×10-9T3+2.33786×1011T4. To complete the fundamental characteristics of these polymorphs we have analysed thermodynamic properties, such as thermal expansion and heat capacity, in a pressure range of 0--40 GPa and a temperature range of 0--1300 K. The obtained results tend to support the available experimental data and other theoretical results. Therefore, the present results indicate that the combination of first principles and a vibrational Debye-like model is an efficient scheme to simulate the high temperature behaviours of Mg2Si.

Key words: semiconductors, thermodynamic properties, phase transition, band structure

中图分类号:  (Phase transitions: general studies)

  • 05.70.Fh
65.40.Ba (Heat capacity) 71.15.Dx (Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)) 73.20.At (Surface states, band structure, electron density of states)