Electronic State and Magnetic Susceptibility in Orbitally Degenerate ( J=5/2) Periodic Anderson Model
Electronic State and Magnetic Susceptibility in Orbitally Degenerate ( J=5/2) Periodic Anderson Model
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轨道简并(J=5/2)周期性安德森模型中的电子态和磁化率
DOI：
10.1143/jpsj.66.2232
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发表时间：
1997
影响因子：
1.7
通讯作者：
K. Yamada
中科院分区：
文献类型：
--
作者：
H. Kontani;K. Yamada
重费米子系统的磁化率由泡利项（χ P）和Van-Vleck项（χ V）组成。后者来自带间激发，其中f轨道简并是必不可少的。在本文中，我们研究了金属和绝缘情况下轨道简并（J =5/2）周期Anderson模型中的χ P和χ V。利用自洽二阶微扰理论研究了f-电子间的关联效应。主要结果如下：(i)六重退化模型：χ P和χ V都被1/ z的因子增强（z是重整化常数）。（ii）非退化模型：只有χ P增强1/ z。因此，轨道简并对于χ V的增强是必不可少的。此外，轨道简并降低了威尔逊比，稳定了非磁性费米液态。
Magnetic susceptibility in a heavy fermion system is composed of the Pauli term (χ P ) and the Van-Vleck term (χ V ). The latter comes from the interband excitation, where f -orbital degeneracy is essential. In this work, we study χ P and χ V in the orbitally degenerate ( J =5/2) periodic Anderson model for both the metallic and insulating cases. The effect of the correlation between f -electrons is investigated using the self-consistent second-order perturbation theory. The main results are as follows. (i) Sixfold degenerate model: both χ P and χ V are enhanced by a factor of 1/ z ( z is the renormalization constant). (ii) Nondegenerate model: only χ P is enhanced by 1/ z . Thus, orbital degeneracy is indispensable for the enhancement of χ V . Moreover, orbital degeneracy reduces the Wilson ratio and stabilizes the nonmagnetic Fermi liquid state.