The screened pseudo-charge repulsive potential in perturbed orbitals for band calculations by DFT plus U
The screened pseudo-charge repulsive potential in perturbed orbitals for band calculations by DFT plus U
复制标题
通过 DFT U 筛选扰动轨道中的赝电荷排斥势以进行能带计算
DOI：
10.1039/c7cp00025a
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发表时间：
2017-03-21
影响因子：
3.3
通讯作者：
Huang, Bolong
中科院分区：
文献类型：
--
作者：
Huang, Bolong
对于满占轨道固体，传统的线性响应在DFT+U计算中高估了U。在这里，我们证明了挑战来自于外部扰动下电子-电子库仑排斥能的不完全抵消。我们应用第二电荷响应，表示为“伪电荷”模型，以抵消这种残留效应。在这两个电荷响应诱导的库仑势之间相互抵消，U参数通过满足最小化非库普曼能量的条件而自一致地获得。此外，伪电荷诱导的排斥势表现出与占据轨道有关的筛选行为，并可能符合筛选的电子的精确交换相关。所得U参数是改进的DFT+U法计算带结构的自洽解。该工作将线性响应方法的有效性扩展到部分和完全占据轨道，并为在其他先进方法之前估计Hubbard U参数提供了参考。在可转移性试验中，采用PBE和混合密度泛函方法确定了U参数，结果表明该方法与泛函无关。给出了用hybrid-DFT+U-hybrid方法确定的电子结构。并与最近发展的自洽混合- dft +U-w方法进行了比较。
The conventional linear response overestimates the U in DFT+U calculations for solids with fully occupied orbitals. Here, we demonstrate that the challenge arises from the incomplete cancellation of the electron-electron Coulomb repulsion energy under external perturbation. We applied the second charge response, denoted as the ``pseudo-charge'' model, to offset such residue effects. Counteracting between these two charge response-induced Coulomb potentials, the U parameters are self-consistently obtained by fulfilling the conditions for minimizing the non-Koopmans energy. Moreover, the pseudo-charge-induced repulsive potential shows a screening behavior related to the orbital occupation and is potentially in compliance with the screened exact exchange-correlation of electrons. The resultant U parameters are self-consistent solutions for improved band structure calculations by the DFT+U method. This work extends the validity of the linear response method to both partially and fully occupied orbitals and gives a reference for estimating the Hubbard U parameter prior to other advanced methods. The U parameters were determined in a transferability test using both PBE and hybrid density functional methods, and the results showed that this method is independent of the functional. The electronic structures determined from the hybrid-DFT+U-hybrid approach are provided. Comparisons are also made with the recently developed self-consistent hybrid-DFT+U-w method.