Electrical and thermal conductivity of Al liquid at high pressures and temperatures from ab initio computations
Electrical and thermal conductivity of Al liquid at high pressures and temperatures from ab initio computations
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DOI：
10.1103/physrevb.85.184201
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发表时间：
2012-05
影响因子：
3.7
通讯作者：
V. Vlček;N. Koker;G. Steinle‐Neumann
中科院分区：
文献类型：
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作者：
V. Vlček;N. Koker;G. Steinle‐Neumann
使用第一原理分子动力学。我们的结果与低压下的测量结果一致，表明在压缩下，电子输运系数σ和κ增大；随着温度的升高，σ减小，κ增大。对压缩和加热的响应行为可以用热激发电子占据导带的变化来解释。基于σ的频率依赖关系，我们进一步证明了铝液在各种条件下都能用德鲁德图很好地描述，从而证实了它的自由电子性质。在高的P和T下，我们计算的σ和κ产生的洛伦兹数比理论值低7%，这表明维德曼-弗兰兹定律在极端条件下仍然近似满足。使用一种电子简单的金属，如液态铝作为更复杂金属行为的指南，我们推断，目前基于外推的地球外核σ和κ估计可能太低了3-4倍。
using first-principles molecular dynamics. Our results are consistent with measurements at low pressures, and indicate that electronic transport coefficients σ and κ increase under compression; with increasing temperature σ decreases and κ increases. Behavior in response to compression and heating are explained in terms of changes in occupation of conduction bands by thermally excited electrons. Based on the frequency dependence of σ, we further show that liquid aluminum is well described by the Drude picture over a wide range of conditions, confirming its free-electron nature. At high P and T, our computed σ and κ yield Lorenz numbers up to 7% lower than the theoretical value, indicating that the Wiedemann-Franz law remains approximately satisfied at extreme conditions. Using an electronically simple metal such as liquid Al as a guide to the behavior of more complex metals, we infer that present extrapolation-based estimates of σ and κ for the Earth’s outer core may be 3‐4 times too low.