Zhang Youjun, Hou Mingqiang, Liu Guangtao, Zhang Chengwei, Prakapenka Vitali B, Greenberg Eran, Fei Yingwei, Cohen R E, Lin Jung-Fu
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201900, China.
Phys Rev Lett. 2020 Aug 14;125(7):078501. doi: 10.1103/PhysRevLett.125.078501.
We measure the electrical resistivity of hcp iron up to ∼170 GPa and ∼3000 K using a four-probe van der Pauw method coupled with homogeneous flattop laser heating in a DAC, and compute its electrical and thermal conductivity by first-principles molecular dynamics including electron-phonon and electron-electron scattering. We find that the measured resistivity of hcp iron increases almost linearly with temperature, and is consistent with our computations. The results constrain the resistivity and thermal conductivity of hcp iron to ∼80±5 μΩ cm and ∼100±10 W m^{-1} K^{-1}, respectively, at conditions near the core-mantle boundary. Our results indicate an adiabatic heat flow of ∼10±1 TW out of the core, supporting a present-day geodynamo driven by thermal and compositional convection.
我们使用四探针范德堡方法结合金刚石对顶砧中均匀平顶激光加热，测量了高达约170吉帕和约3000开尔文的六方密排铁的电阻率，并通过包括电子 - 声子和电子 - 电子散射的第一性原理分子动力学计算其电导率和热导率。我们发现，测量的六方密排铁的电阻率几乎随温度呈线性增加，并且与我们的计算结果一致。结果将六方密排铁在接近核幔边界条件下的电阻率和热导率分别限制在约80±5微欧厘米和约100±10瓦米⁻¹开⁻¹。我们的结果表明，从地核向外的绝热热流约为10±1太瓦，支持了由热对流和成分对流驱动的现代地球发电机。
