中国物理B ›› 2013, Vol. 22 ›› Issue (2): 23104-023104.doi: 10.1088/1674-1056/22/2/023104

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

Pressure-induced phase transition in silicon nitride material

陈东, 余本海   

  1. College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China
  • 收稿日期:2012-04-21 修回日期:2012-07-16 出版日期:2013-01-01 发布日期:2013-01-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11005088 and 11105115); the Project of Basic and Advanced Technology of Henan Province of China (Grant No. 112300410021); and the Key Project of Henan Educational Committee (Grant No. 12A140010).

Pressure-induced phase transition in silicon nitride material

Chen Dong (陈东), Yu Ben-Hai (余本海)   

  1. College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China
  • Received:2012-04-21 Revised:2012-07-16 Online:2013-01-01 Published:2013-01-01
  • Contact: Yu Ben-Hai E-mail:chchendong2010@163.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11005088 and 11105115); the Project of Basic and Advanced Technology of Henan Province of China (Grant No. 112300410021); and the Key Project of Henan Educational Committee (Grant No. 12A140010).

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摘要： The equilibrium crystal structures, lattice parameters, elastic constants, and elastic moduli of the polymorphs α-, β-, and γ-Si3N4, have been calculated by first-principles method. β-Si3N4 is ductile in nature and has an ionic bonding. γ-Si3N4 is found to be a brittle material and has covalent chemical bonds, especially at high pressures. The phase boundary of the β → γ transition is obtained and a positive slope is found. This indicates that at higher temperatures it requires higher pressures to synthesize γ-Si3N4. On the other hand, the α → γ phase boundary can be described as P=14.37198+3.27×10-3T-7.83911×10-7T2-3.13552×1010T3. The phase transition from α- to γ-Si3N4 occurs at 16.1~GPa and 1700~K. Then, the dependencies of bulk modulus, heat capacity, and thermal expansion on the pressure P are obtained in the ranges of 0~GPa-30~GPa and 0~K-2000~K. Significant features in these properties are observed at high temperatures. It turns out that the thermal expansion of γ-Si3N4 is larger than that of α-Si3N4 over wide pressure and temperature ranges. The evolutions of the heat capacity with temperature for the Si3N4 polymorphs are close to each other, which are important for possible applications of Si3N4.

关键词: density functional theory, semiconductor, heat capacity, bulk modulus

Abstract: The equilibrium crystal structures, lattice parameters, elastic constants, and elastic moduli of the polymorphs α-, β-, and γ-Si3N4, have been calculated by first-principles method. β-Si3N4 is ductile in nature and has an ionic bonding. γ-Si3N4 is found to be a brittle material and has covalent chemical bonds, especially at high pressures. The phase boundary of the β → γ transition is obtained and a positive slope is found. This indicates that at higher temperatures it requires higher pressures to synthesize γ-Si3N4. On the other hand, the α → γ phase boundary can be described as P=14.37198+3.27×10-3T-7.83911×10-7T2-3.13552×1010T3. The phase transition from α- to γ-Si3N4 occurs at 16.1~GPa and 1700~K. Then, the dependencies of bulk modulus, heat capacity, and thermal expansion on the pressure P are obtained in the ranges of 0~GPa-30~GPa and 0~K-2000~K. Significant features in these properties are observed at high temperatures. It turns out that the thermal expansion of γ-Si3N4 is larger than that of α-Si3N4 over wide pressure and temperature ranges. The evolutions of the heat capacity with temperature for the Si3N4 polymorphs are close to each other, which are important for possible applications of Si3N4.

Key words: density functional theory, semiconductor, heat capacity, bulk modulus

中图分类号: 

  • 31.15.E-
61.72.uj (III-V and II-VI semiconductors) 65.40.Ba (Heat capacity)