Symmetry-breaking polymorphous descriptions for correlated materials without interelectronic U
Symmetry-breaking polymorphous descriptions for correlated materials without interelectronic U
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DOI：
10.1103/physrevb.102.045112
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发表时间：
2019-06
影响因子：
3.7
通讯作者：
Yubo Zhang;J. Furness;Ruiqi Zhang;Zhi Wang;A. Zunger;Jianwei Sun
中科院分区：
文献类型：
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作者：
Yubo Zhang;J. Furness;Ruiqi Zhang;Zhi Wang;A. Zunger;Jianwei Sun
具有简并带边态的开壳层d-和f-离子的相关材料显示出丰富多样的有趣性质，从金属-绝缘体转变到非常规的超导性。这些材料的电子结构的教科书观点是平均场方法是不合适的，因为电子间相互作用U需要在占据和未占据简并态之间打开带隙，同时保持对称性。我们表明，后者的情况下，往往定义莫特绝缘体，实际上是不需要的三维二元氧化物MnO，FeO，CoO和NiO。平均场能带理论确实可以解除这种退化的二进制时，非平凡的单胞表示（多态网络）被允许打破对称性，结合最近开发的非经验的交换和相关密度泛函没有现场interelectronic相互作用U。我们解释了如何密度泛函理论（DFT）在多晶型表示实现带隙开放相关材料通过一个单独的机制，以莫特-哈伯德的方法。我们表明，该方法预测的磁矩和间隙的四个二元一氧化物在反铁磁和顺磁相，提供了一个有效的替代方法来研究一系列的功能，在开放的d-和f-壳层复杂的材料。
Correlated materials with open-shell d- and f-ions having degenerate band edge states show a rich variety of interesting properties ranging from metal-insulator transition to unconventional superconductivity. The textbook view for the electronic structure of these materials is that mean-field approaches are inappropriate, as the interelectronic interaction U is required to open a band gap between the occupied and unoccupied degenerate states while retaining symmetry. We show that the latter scenario often defining what Mott insulators are, is in fact not needed for the 3d binary oxides MnO, FeO, CoO, and NiO. The mean-field band theory can indeed lift such degeneracies in the binaries when nontrivial unit cell representations (polymorphous networks) are allowed to break symmetries, in conjunction with a recently developed non-empirical exchange and correlation density-functional without an on-site interelectronic interaction U. We explain how density-functional theory (DFT) in the polymorphous representation achieves band gap opening in correlated materials through a separate mechanism to the Mott-Hubbard approach. We show the method predicts magnetic moments and gaps for the four binary monoxides in both the antiferromagnetic and paramagnetic phases, offering an effective alternative to symmetry-conserving approaches for studying a range of functionalities in open d- and f-shell complex materials.