中国物理B ›› 2014, Vol. 23 ›› Issue (12): 127101-127101.doi: 10.1088/1674-1056/23/12/127101

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Mechanical and thermodynamic properties of the monoclinic and orthorhombic phases of SiC2N4 under high pressure from first principles

苗楠茜a, 濮春英a, 何朝政a, 张飞武b c, 卢成a, 卢志文a, 周大伟a   

  1. a College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China;
    b Nanochemistry Research Institute, Curtin University, Perth, WA-6845, Australia;
    c State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
  • 收稿日期:2014-04-27 修回日期:2014-06-15 出版日期:2014-12-15 发布日期:2014-12-15
  • 基金资助:
    Projected supported by the Henan Joint Funds of the National Natural Science Foundation of China (Grant Nos. U1304612, U1404608, and U1404216), the Special Fund for the Theoretical Physics of China (Grant No. 11247222), the Nanyang Normal University Science Foundation, China (Grant Nos. ZX2010011, ZX2012018, and ZX2014088), the National Natural Science Foundation of China (Grant Nos. 11304167 and 51374132), the Postdoctoral Science Foundation of China (Grant No. 20110491317), and the Young Core Instructor Foundation of Henan Province, China (Grant No. 2012GGJS-152).

Mechanical and thermodynamic properties of the monoclinic and orthorhombic phases of SiC2N4 under high pressure from first principles

Miao Nan-Xi (苗楠茜)a, Pu Chun-Ying (濮春英)a, He Chao-Zheng (何朝政)a, Zhang Fei-Wu (张飞武)b c, Lu Cheng (卢成)a, Lu Zhi-Wen (卢志文)a, Zhou Da-Wei (周大伟)a   

  1. a College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China;
    b Nanochemistry Research Institute, Curtin University, Perth, WA-6845, Australia;
    c State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
  • Received:2014-04-27 Revised:2014-06-15 Online:2014-12-15 Published:2014-12-15
  • Contact: Zhou Da-Wei E-mail:zhoudawei@nynu.edu.cn
  • Supported by:
    Projected supported by the Henan Joint Funds of the National Natural Science Foundation of China (Grant Nos. U1304612, U1404608, and U1404216), the Special Fund for the Theoretical Physics of China (Grant No. 11247222), the Nanyang Normal University Science Foundation, China (Grant Nos. ZX2010011, ZX2012018, and ZX2014088), the National Natural Science Foundation of China (Grant Nos. 11304167 and 51374132), the Postdoctoral Science Foundation of China (Grant No. 20110491317), and the Young Core Instructor Foundation of Henan Province, China (Grant No. 2012GGJS-152).

摘要: First principles calculations are preformed to systematically investigate the electronic structures, elastic and thermodynamic properties of the monoclinic and orthorhombic phases of SiC2N4 under pressure. The calculated structural parameters and elastic moduli are in good agreement with the available theoretical values at zero pressure. The elastic constants of the two phases under pressure are calculated by stress–strain method. It is found that both phases satisfy the mechanical stability criteria within 60 GPa. With the increase of pressure, the degree of the anisotropy decreases rapidly in the monoclinic phase, whereas it remains almost constant in the orthorhombic phase. Furthermore, using the hybrid density-functional theory, the monoclinic and orthorhombic phases are found to be wide band-gap semiconductors with band gaps of about 2.85 eV and 3.21 eV, respectively. The elastic moduli, ductile or brittle behaviors, compressional and shear wave velocities as well as Debye temperatures as a function of pressure in both phases are also investigated in detail.

关键词: SiC2N4, density functional theory, Debye temperature, elastic anisotropy

Abstract: First principles calculations are preformed to systematically investigate the electronic structures, elastic and thermodynamic properties of the monoclinic and orthorhombic phases of SiC2N4 under pressure. The calculated structural parameters and elastic moduli are in good agreement with the available theoretical values at zero pressure. The elastic constants of the two phases under pressure are calculated by stress–strain method. It is found that both phases satisfy the mechanical stability criteria within 60 GPa. With the increase of pressure, the degree of the anisotropy decreases rapidly in the monoclinic phase, whereas it remains almost constant in the orthorhombic phase. Furthermore, using the hybrid density-functional theory, the monoclinic and orthorhombic phases are found to be wide band-gap semiconductors with band gaps of about 2.85 eV and 3.21 eV, respectively. The elastic moduli, ductile or brittle behaviors, compressional and shear wave velocities as well as Debye temperatures as a function of pressure in both phases are also investigated in detail.

Key words: SiC2N4, density functional theory, Debye temperature, elastic anisotropy

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

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62.20.D- (Elasticity) 71.20.-b (Electron density of states and band structure of crystalline solids)