New development beyond the GW approximation and its application to the electronic structure of solids

1. Takada根据他自己的理论计算了电子液体的准粒子能量，该理论使人们能够通过迭代考虑所有费曼图的自能，这需要在守恒近似方法的框架中使用泡利原理。然后他得到了Yasuhara等人（1999）的相同结论，即从角分辨光电发射实验中预测的简单金属占用带宽的缩小实际上归因于传统上使用自由电子能作为最终态能级，相反，如果使用准粒子能，则在交换和相关的影响下带宽有所增加。他的计算首次允许单对（或等离子激元）和多对激发不可分割的耦合。2. 利用同样的理论，Takada还计算了整个金属密度区域内电子液的动力结构因子S(q,ω)，发现在低ω处单对激励引起的ω-线性谱形被粒子空穴多重散射增强，而在中间ω处单对和多对激励之间的相消干涉产生了泛谱结构。这些与传统的RPA光谱形状有很大不同。3. 石原等人利用Yasuhara-Takada理论（1991）对钠进行了波段计算，发现在交换和相关的影响下，其占用的带宽增加了不到10%。他们确定了完美球中钠的费米表面畸变是由赝势决定的，而不受传导电子之间的交换和关联的影响。4. Yasuhara和Higuchi从电子液体中借鉴了长、中、短程相关的知识，结合轨道相关的交换能泛函，构建了一个轨道相关的能带计算相关能泛函。他们预测，重费米子系统可能会被解释为在费米能级附近的Kohn-Sham轨道的相关诱导重建，在那里，通过混合传导轨道和f电子轨道，态的密度得到了极大的增强，从而获得了依赖轨道的相关能泛函数的大小。少

1. Takada has calculated the quasiparticle energy of the electron liquid, based on his own theory that enables one to consider by iteration all Feynman diagrams for the self-energy by requiring the Pauli principle in the framework of the conserving approximation method. He has then obtained the same conclusion by Yasuhara et al (1999) that the narrowing in the occupied bandwidth of simple metals predicted from angular resolved photoemission experiments is in fact ascribed to the traditional use of the free electron energy as the final state level and on the contrary the bandwidth is somewhat increased under the influence of exchange and correlation if one uses the quasiparticle energy instead. His calculation has for the first time allowed for an inseparable coupling of one-pair (or plasmon) and multi-pair excitations. 2. Using the same theory Takada has also calculated the dynamical structure factor S(q,ω) of the electron liquid over the entire region of metallic densities and found t … More hat the ω-linear spectral shape due to one-pair excitations at low ω is enhanced by particlehole multiple scattering and the destructive interference between one and multi-pair excitations produces a flauened spectral structure at intermediate ω. These are quite different from the conventional RPA spectral shape. 3. Using the Yasuhara-Takada theory (1991) Ishihara et al have performed a band calculation of sodium and found that its occupied bandwidth is by less than 10% increased under the influence of exchange and correlation. They have ascertained that the Fermi surface distortion of sodium from the perfect sphere is determined by the pseudo-potential, not influenced by exchange and correlation between conduction electrons. 4. Yasuhara and Higuchi have constructed an orbital-dependent correlation energy functional for use in band calculations in combination with the orbital-dependent exchange energy functional, borrowing the knowledge of long-, intermediate-, and short-range correlations from the electron liquid. They have predicted that heavy fermion systems probably will be interpreted in terms of the correlation-induced reconstruction of Kohn-Sham orbitals in the vicinity of the Fermi level where the density of states is extraordiarily enhaced by mixing conduction and f-electron orbitals to gain the magnitude of that orbital-dependent correlation energy functional. Less