Fe-3.24%Si的状态方程和声速的第一性原理计算:地球内核Si元素的约束

李佩芸 黄海军 李艳丽

李佩芸, 黄海军, 李艳丽. Fe-3.24%Si的状态方程和声速的第一性原理计算:地球内核Si元素的约束[J]. 高压物理学报, 2019, 33(6): 060101. doi: 10.11858/gywlxb.20190781
引用本文: 李佩芸, 黄海军, 李艳丽. Fe-3.24%Si的状态方程和声速的第一性原理计算:地球内核Si元素的约束[J]. 高压物理学报, 2019, 33(6): 060101. doi: 10.11858/gywlxb.20190781
LI Peiyun, HUANG Haijun, LI Yanli. First-Principles Calculations of the Equation of State and Sound Velocity of Fe-3.24%Si: Implications for the Composition of Earth’s Inner Core[J]. Chinese Journal of High Pressure Physics, 2019, 33(6): 060101. doi: 10.11858/gywlxb.20190781
Citation: LI Peiyun, HUANG Haijun, LI Yanli. First-Principles Calculations of the Equation of State and Sound Velocity of Fe-3.24%Si: Implications for the Composition of Earth’s Inner Core[J]. Chinese Journal of High Pressure Physics, 2019, 33(6): 060101. doi: 10.11858/gywlxb.20190781

Fe-3.24%Si的状态方程和声速的第一性原理计算:地球内核Si元素的约束

doi: 10.11858/gywlxb.20190781
基金项目: 国家自然科学基金(41874103);中央高校基本科研经费(2017IB013,2018IB009,2018B011)
详细信息
    作者简介:

    李佩芸(1994-),女,硕士研究生,主要从事第一性原理计算研究. E-mail:lipeiyun@whut.edu.cn

    通讯作者:

    李艳丽(1977-),女,博士,副教授,主要从事第一性原理研究.E-mail:liyanli128@whut.edu.cn

  • 中图分类号: O521.2

First-Principles Calculations of the Equation of State and Sound Velocity of Fe-3.24%Si: Implications for the Composition of Earth’s Inner Core

  • 摘要: 硅(Si)被认为是地球内核的主要轻元素,但其在内地核中的含量仍然存在争议。为了探索内地核中Si的含量,应用第一性原理方法对Fe-3.24%Si(Si的质量分数为3.24%)进行了研究。构造了4种Fe-3.24%Si的超晶胞,研究了不同的晶胞大小和自旋对优化结构的影响。结果表明:在100 GPa以上,自旋对Fe-3.24%Si的密度无影响;而在100 GPa以下,考虑自旋时的计算结果更接近实验值。基于0 K下的声速、状态方程和相关热力学参数,计算了Fe-3.24%Si在内地核条件下的密度和声速。研究发现:Fe-3.24%Si的密度低于纯铁的密度,略高于内地核的密度;纵波声速及剪切波声速与纯铁的声速很接近,但均明显高于内地核声速,因此排除了内地核含有大量Si元素的可能性。

     

  • 图  hcp-Fe-3.24%Si的结构

    Figure  1.  Structure of hcp-Fe-3.24%Si

    图  单位体积内的能量e随压力的变化

    Figure  2.  Variation of the energy per unit volume e versus pressure

    图  Fe-3.24%Si的压力随密度的变化

    Figure  3.  Calculated density vs. pressure for Fe-3.24%Si

    图  0 K状态下Fe-3.24%Si的声速与密度的关系

    Figure  4.  Sound velocity of Fe-3.24%Si versus density at 0 K

    图  内地核条件下Fe-3.24%Si的密度、纵波声速vp、体波声速vb和横波声速vs与铁和内地核的数据比较

    Figure  5.  Comparison of the density, longitudinal sound velocity vp, bulk sound velocity vb and shear velocity vs of Fe-3.24%Si with those of Fe and the data of the inner core

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  • 收稿日期:  2019-05-22
  • 修回日期:  2019-06-26
  • 发布日期:  2019-09-25

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