Many-body renormalization of forces in f -electron materials
Many-body renormalization of forces in f -electron materials
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DOI：
10.1103/physrevb.98.075129
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发表时间：
2018-04
影响因子：
3.7
通讯作者：
E. Plekhanov;P. Hasnip;V. Sacksteder;Matt Probert;S. Clark;K. Refson;C. Weber
中科院分区：
文献类型：
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作者：
E. Plekhanov;P. Hasnip;V. Sacksteder;Matt Probert;S. Clark;K. Refson;C. Weber
我们提出的实施动态平均场理论（DMFT）的CASTEP从头算代码。我们详细解释了DFT+DMFT的理论框架，并通过使用Hubbard I求解器演示了我们对三个具有f -壳层电子的强关联系统：γ -铈，三氧化二铈Ce 2 O3和碲化钐SmTe的实现。我们发现非常好的协议与以前的基准DFT+DMFT计算的铈化合物，而SmTe，我们表现出改进的协议与实验结构参数相比，LDA。我们的实现同样适用于正常保存和超软赝势，我们将其应用到计算的总能量，体积模量，平衡体积，和内力在两个铈化合物。在Ce 2 O3中，我们报告了作用于不受晶胞对称性约束的坐标上的内力的急剧减少。这种减少是由多体效应引起的，只能在DMFT水平上捕获。此外，我们推导出另一种形式，用于治疗的绿色函数的高频尾巴在松原频率求和。我们的治疗允许减少的偏见时，计算的相关能量和占领矩阵，以高精度。
We present the implementation of dynamical mean-field theory (DMFT) in the CASTEP ab initio code. We explain in detail the theoretical framework for DFT+DMFT and we demonstrate our implementation for three strongly-correlated systems with f -shell electrons: γ -cerium, cerium sesquioxide Ce2O3, and samarium telluride SmTe by using a Hubbard I solver. We find very good agreement with previous benchmark DFT+DMFT calculations of cerium compounds, while for SmTe we show the improved agreement with the experimental structural parameters as compared with LDA. Our implementation works equally well for both norm-conserving and ultrasoft pseudopotentials, and we apply it to the calculation of total energy, bulk modulus, equilibrium volumes, and internal forces in the two cerium compounds. In Ce2O3 we report a dramatic reduction of the internal forces acting on coordinates not constrained by unit cell symmetries. This reduction is induced by the many-body effects, which can only be captured at the DMFT level. In addition, we derive an alternative form for treating the high-frequency tails of the Green function in Matsubara frequency summations. Our treatment allows a reduction in the bias when calculating the correlation energies and occupation matrices to high precision.