1 N expansion for the Kondo lattice
1 N expansion for the Kondo lattice
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Kondo 晶格的 1 N 展开
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
P. Coleman
中科院分区：
文献类型：
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作者：
P. Coleman
通过Coqblin-Schrieffer交换相互作用，给出了自旋为j的局域矩晶格与能带相互作用的配分函数的图解展开。通过考察大自旋简并极限$N=2J+1$，得到了配分函数的$Frc{1}{N}$展开式，它清楚地展示了大自旋简并如何增强局域自旋涨落。用标度理论考察了Ruderman-Kittel-Kasuya-Yosida相互作用与局域Kondo自旋涨落之间的竞争关系，得到了自旋补偿Kondo晶格基态稳定的Kondo耦合常数的临界值为$O(Frc{1}{N})$，为Kondo晶格模型在稀土体系中的适用性提供了新的依据。基于强耦合区交叉的性质，提出了物理论证，认为Kondo晶格的低温激发形成了一个重费米子的窄带。
A diagrammatic expansion is developed for the partition function of a lattice of spin-$j$ local moments interacting with a band via the Coqblin-Schrieffer exchange interaction. By examining the limit of large spin degeneracy, $N=2j+1$, a $frac{1}{N}$ expansion is obtained for the partition function, which clearly exhibits how local spin fluctuations are enhanced by large spin degeneracy. The competition between the Ruderman-Kittel-Kasuya-Yosida interaction and local Kondo spin fluctuations is examined using scaling theory, and the critical value of the Kondo coupling constant above which a spin-compensated Kondo-lattice ground state is stable is shown to tend to zero as $O(frac{1}{N})$, providing new justification for the applicability of the Kondo-lattice model to rare-earth systems. Physical arguments are advanced, based on the nature of the crossover to the strong-coupling regime, which suggest that the low-temperature excitations of the Kondo lattice form a narrow band of heavy fermions.