Origins of the attractive interactions for the Cooper pairs in dense Kondo systems.
Origins of the attractive interactions for the Cooper pairs in dense Kondo systems.
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密集近藤系统中库珀对吸引力相互作用的起源。
DOI：
10.1103/physrevb.35.1692
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Kuroda
中科院分区：
文献类型：
--
作者：
Jichu;Nagi;Jin;Matsuura;Kuroda
Jichu，Matsuura和黑田提出了处理周期安德森模型的一般方法，并证明了存在带宽为O（T K）（T K是近藤温度）的准粒子，这可以解释实验中观察到的重费米子。在本研究中，我们应用这样的程序来调查的准粒子相互作用的库珀配对系统中的起源。我们发现：（1）费米-液体相互作用，特别是由准粒子自身的自旋密度和电荷密度涨落所介导的，一般具有O（T K）的强度;（2）通过近藤效应的调制，准粒子-声子耦合与费米能级以上的电子能量成正比，这与文献中已有的模型假设明显不同.相应地，声子介导的准粒子配对相互作用具有特殊的频率依赖性，因此，相互作用只在强耦合情况下起重要作用。在CeCu 2 Si 2等材料中观察到的超导电性可以作为此类情况的例子。
Jichu, Matsuura, and Kuroda proposed a general procedure for treating the periodic Anderson model and showed that there exist quasiparticles with bandwidth of O (T K)(T K is the Kondo temperature), which account for the heavy fermions observed in the experiments. In the present study, we apply such a procedure to investigate the origins of the quasiparticle interaction for the Cooper pairing in the system. We find that (1) the Fermi-liquid interaction, specifically mediated by the spin-density and the charge-density fluctuations of the quasi-particles themselves, generally has strength of O (T K);(2) the quasiparticle-phonon coupling through modulation of the Kondo effect is proportional to the electronic energy above the Fermi level, which is in significant contrast to the models assumed in the earlier studies available in literature. Correspondingly, the phonon-mediated quasiparticle-pairing interaction has a peculiar frequency dependence, because of which the interaction plays an appreciable role only in strong-coupling cases. The superconductivity observed in the materials like CeCu 2 Si 2 can be examples for such cases.