GW approximation with LSDA + U method and applications to NiO, MnO, and V 2 O 3
GW approximation with LSDA + U method and applications to NiO, MnO, and V 2 O 3
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DOI：
10.1103/physrevb.78.155112
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发表时间：
2008-09
影响因子：
3.7
通讯作者：
S. Kobayashi;Y. Nohara;S. Yamamoto;T. Fujiwara
中科院分区：
文献类型：
--
作者：
S. Kobayashi;Y. Nohara;S. Yamamoto;T. Fujiwara
提出了一种名为 $\text{U}+\text{GWA}$ 的 GW 近似（GWA）方法，其中我们可以使用通过局域自旋密度近似 $(\text{LSDA})+\text{U}$ 方法获得的更局域波函数来启动 GWA。然后将 GWA 和 $\text{U}+\text{GWA}$ 应用于反铁磁相的 MnO、NiO 和 ${\text{V}}_{2}{\text{O}}_{3}$。带隙和能谱与实验观察到的结果非常吻合，并进行了详细讨论。计算出的${\text{V}}_{2}{\text{O}}_{3}$的$d$能带宽度比观察到的要窄得多，可能是${t}_{2g}^{2}$多重态和单电子${t}_{2g}$能级的混合。 GWA 或 $\text{U}+\text{GWA}$ 在 ${\text{V}}_{2}{\text{O}}_{3}$ 的顺磁相中也不起作用，其原因已阐明。详细讨论了现场库仑相互作用的唯一选择方法。讨论了我们是否应该采用 GWA 还是 $\text{U}+\text{GWA}$ 的标准，并借助自能的非对角元素进行评估。
A GW approximation (GWA) method named $\text{U}+\text{GWA}$ is proposed, where we can start GWA with more localized wave functions obtained by the local spin-density approximation $(\text{LSDA})+\text{U}$ method. Then GWA and $\text{U}+\text{GWA}$ are applied to MnO, NiO, and ${\text{V}}_{2}{\text{O}}_{3}$ in antiferromagnetic phase. The band gaps and energy spectra show excellent agreement with the experimentally observed results and are discussed in detail. The calculated width of $d$ bands of ${\text{V}}_{2}{\text{O}}_{3}$ is much narrower than that of the observed one which may be a mixture of ${t}_{2g}^{2}$ multiplet and single-electron ${t}_{2g}$ level. GWA or $\text{U}+\text{GWA}$ does not work also in the paramagnetic phase of ${\text{V}}_{2}{\text{O}}_{3}$ and the reason for this is clarified. The method of the unique choice of on-site Coulomb interaction is discussed in detail. The criterion for whether we should adopt GWA or $\text{U}+\text{GWA}$ is discussed and is assessed with the help of the off-diagonal elements of the self-energy.