Fully consistent density functional theory determination of the insulator-metal transition boundary in warm dense hydrogen
Fully consistent density functional theory determination of the insulator-metal transition boundary in warm dense hydrogen
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DOI：
10.1103/physrevresearch.2.032065
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
J. Hinz;V. Karasiev;Suxing Hu;M. Zaghoo;D. Mejía-Rodríguez;S. Trickey;L. Calderin
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文献类型：
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作者：
J. Hinz;V. Karasiev;Suxing Hu;M. Zaghoo;D. Mejía-Rodríguez;S. Trickey;L. Calderin
在从头算分子动力学模拟中，利用概念上和程序上一致的密度泛函理论（DFT）计算和先进的meta-GGA交换相关泛函，我们确定了热致密流体氢在50至300 GPa压力范围内的绝缘体-金属转变（IMT）。与Born-Oppenheimer (BO) MD的结果相比，通过路径积分分子动力学（PIMD）包含的核量子效应使金属转变更加尖锐，并降低了转变温度。与之前的DFT预测相比，BOMD本身与实验结果的一致性得到了改善。在过渡时电导率突然增加的背景下，对离子对相关函数的检查证实了由于分子氢的解离引起的金属过渡与突然的带隙关闭相吻合。直接比较PIMD和BOMD的结果清楚地表明同位素对IMT的影响。与随机模拟不同，这些结果不依赖于基态和有限t方法的任何特别组合。
Using conceptually and procedurally consistent density functional theory (DFT) calculations with an advanced meta-GGA exchange-correlation functional in ab initio molecular dynamics simulations, we determine the insulator-metal transition (IMT) of warm dense fluid hydrogen over the pressure range 50 to 300 GPa. Inclusion of nuclear quantum effects via path-integral molecular dynamics (PIMD) sharpens the metallic transition and lowers the transition temperature relative to results from Born-Oppenheimer (BO) MD. BOMD itself gives improved agreement with experimental results compared to previous DFT predictions. Examination of the ionic pair correlation function in the context of the abrupt conductivity increase at the transition confirms a metallic transition due to the dissociation of molecular hydrogen that coincides with an abrupt band gap closure. Direct comparison of the PIMD and BOMD results clearly demonstrates an isotope effect on the IMT. Distinct from stochastic simulations, these results do not depend upon any ad hoc combination of ground-state and finite-T methodologies.