$\alpha -$ to $\beta $- to $\gamma $-spinel transformations in Mg$_{2}$SiO$_{4}$.

ORAL

Abstract

Phase relations in Mg$_{2}$SiO$_{4}$ have been investigated by first principles quasiharmonic calculations. The $\alpha $- to $\beta $-spinel transition is believed to cause the 410-km discontinuity, while the $\beta $- to $\gamma $-spinel transformation may contribute to the 520-km discontinuity. We have obtained these phase boundaries using LDA and PBE/GGA exchange correlation functionals and results confirm the trend usually displayed by these functionals. Information on this series of transformations in Mg$_{2}$SiO$_{4}$ will help us understand the importance of other elements on this sequence of phase transformations across the Earth's transition zone.

*Research supported by NSF/EAR 013533, NSF/EAR 0230319, and NSF/ITR 0428774(VLab)

–

Authors

  • Zhongqing Wu

    • Minnesota Supercomputing Institute and Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE

  • Yonggang Yu

    • Minnesota Supercomputing Institute and Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE

  • Renata M. Wentzcovitch

    • University of Minnesota
    • Minnesota Supercomputing Institute, Department od Chemical Engineering and Materials Science, University of Minnesota
    • Minnesota Supercomputing Institute and Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE
    • Minnesota Supercomputing Institute, Department of Chemical Engineering and Materials Science, University of Minnesota