Acta Physica Sinica, Volume. 69, Issue 15, 156202-1(2020)

Numerical prediction of structural stability and thermodynamic properties for MgF2 with fluorite- type structure under high pressure

Xiao-Wei Sun1,*... Ting Song1, Zi-Jiang Liu1,2, Gui-Xin Wan1, Lei Zhang1 and Wen-Li Chang1 |Show fewer author(s)
Author Affiliations
  • 1School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
  • 2Department of Physics, Lanzhou City University, Lanzhou 730070, China
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    Figures & Tables(11)
    Crystal structures of MgF2 with (a) the rutile-type phase and (b) the fluorite-type phase. The large and small spheres represent magnesium and fluorine atoms, respectively.
    Calculated enthalpy as a function of pressure in the framework of (a) GGA and (b) LDA for MgF2 with the rutile-type and fluorite-type structures at zero temperature. In the inset, the relative enthalpy versus pressure is presented.
    Calculated band structures of MgF2 using GGA method: (a) The rutile-type phases at 0 and 19.26 GPa; (b) the fluorite-type phase at 19.26 and 135 GPa.
    Calculated phonon spectra of MgF2 with the rutile-type phases at (a) 0 GPa and (b) 19.26 GPa and with (c) the fluorite-type phase at 135 GPa using GGA method.
    Pressure dependence of the elastic constants Cij for MgF2 with the fluorite-type structure.
    Volume ratios of MgF2 with the fluorite-type structure obtained from molecular dynamics simulations and first-principles calculations: (a) Volume ratios under different pressures at 300 K; (b) volume ratios under different temperatures at 50 GPa, where in the inset, the data at 0.1 MPa is presented.
    Energy as a function of primitive cell volume for MgF2 with the fluorite-type structure using GGA and LDA calculations.
    (a) Molar volume and (b) total energy of MgF2 with the fluorite-type structure as a function of temperature under different pressures calculated by molecular dynamics.
    Melting phase diagram of MgF2 with the fluorite-type structure obtained from molecular dynamics (MD) simulations, in comparison with the calculated melting phase diagram of the rocksalt phase of MgO.
    Predicted volume thermal expansion coefficient α, isothermal bulk modulus KT, and thermoelastic parameter αKT of MgF2 with the fluorite-type structure as a function of pressure at 300 K and other different temperatures (500, 1000 and 1500 K).
    Predicted volume thermal expansion coefficient α, isothermal bulk modulus KT, and thermoelastic parameter αKT of MgF2 with the fluorite-type structure as a function of temperature at 0.1 MPa and other different pressures (50, 100 and 135 GPa).
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    Xiao-Wei Sun, Ting Song, Zi-Jiang Liu, Gui-Xin Wan, Lei Zhang, Wen-Li Chang. Numerical prediction of structural stability and thermodynamic properties for MgF2 with fluorite- type structure under high pressure [J]. Acta Physica Sinica, 2020, 69(15): 156202-1

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    Paper Information

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    Received: Feb. 26, 2020

    Accepted: --

    Published Online: Dec. 30, 2020

    The Author Email:

    DOI:10.7498/aps.69.20200289

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