Elastic properties of CaCO3 high pressure phases from first principles  

作　　者：黄丹 刘红 侯明强 谢梦雨 鹿亚飞 刘雷 易丽 崔月菊 李营 邓力维 杜建国 

机构地区：[1]CEA Key Laboratory of Earthquake Prediction(Institute of Earthquake Science),China Earthquake Administration(CEA),Beijing 100036,China [2]National Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621900,China [3]Center for High Pressure Science and Technology Advanced Research,Shanghai 201203,China [4]Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Chinese Physics B》2017年第8期587-594,共8页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41174071,41373060,41374096,and 41403099);the Seismic Fund of Institute of Earthquake Science,China Earthquake Administration(CEA)(Grant Nos.2012IES0408,2014IES0407,and 2016IES0101)

摘　　要：Elastic properties of three high pressure polymorphs of CaCO_3 are investigated based on first principles calculations.The calculations are conducted at 0 GPa–40 GPa for aragonite, 40 GPa–65 GPa for post-aragonite, and 65 GPa–150 GPa for the P2_1/c-h-CaCO_3 structure, respectively. By fitting the third-order Birch–Murnaghan equation of state（EOS）, the values of bulk modulus K_0 and pressure derivative K~＇_0 are 66.09 GPa and 4.64 for aragonite, 81.93 GPa and 4.49 for post-aragonite, and 56.55 GPa and 5.40 for P2_1/c-h-CaCO_3, respectively, which are in good agreement with previous experimental and theoretical data. Elastic constants, wave velocities, and wave velocity anisotropies of the three highpressure CaCO_3 phases are obtained. Post-aragonite exhibits 25.90%–32.10% V_P anisotropy and 74.34%–104.30% V_S splitting anisotropy, and P2_1/c-h-CaCO_3 shows 22.30%–25.40% V_Panisotropy and 42.81%–48.00% V_S splitting anisotropy in the calculated pressure range. Compared with major minerals of the lower mantle, CaCO_3 high pressure polymorphs have low isotropic wave velocity and high wave velocity anisotropies. These results are important for understanding the deep carbon cycle and seismic wave velocity structure in the lower mantle.Elastic properties of three high pressure polymorphs of CaCO_3 are investigated based on first principles calculations.The calculations are conducted at 0 GPa–40 GPa for aragonite, 40 GPa–65 GPa for post-aragonite, and 65 GPa–150 GPa for the P2_1/c-h-CaCO_3 structure, respectively. By fitting the third-order Birch–Murnaghan equation of state（EOS）, the values of bulk modulus K_0 and pressure derivative K~＇_0 are 66.09 GPa and 4.64 for aragonite, 81.93 GPa and 4.49 for post-aragonite, and 56.55 GPa and 5.40 for P2_1/c-h-CaCO_3, respectively, which are in good agreement with previous experimental and theoretical data. Elastic constants, wave velocities, and wave velocity anisotropies of the three highpressure CaCO_3 phases are obtained. Post-aragonite exhibits 25.90%–32.10% V_P anisotropy and 74.34%–104.30% V_S splitting anisotropy, and P2_1/c-h-CaCO_3 shows 22.30%–25.40% V_Panisotropy and 42.81%–48.00% V_S splitting anisotropy in the calculated pressure range. Compared with major minerals of the lower mantle, CaCO_3 high pressure polymorphs have low isotropic wave velocity and high wave velocity anisotropies. These results are important for understanding the deep carbon cycle and seismic wave velocity structure in the lower mantle.

关 键 词：CACO3 elastic properties wave velocity anisotropy first principles 

分 类 号：O521[理学—高压高温物理]