ELECTROMAGNETIC ABSORPTION IN ANISOTROPIC SUPERCONDUCTORS
ELECTROMAGNETIC ABSORPTION IN ANISOTROPIC SUPERCONDUCTORS
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DOI：
10.1103/physrevb.40.6695
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发表时间：
1989-10-01
影响因子：
3.7
通讯作者：
PUTIKKA, WO
中科院分区：
文献类型：
--
作者：
HIRSCHFELD, PJ;WOLFLE, P;PUTIKKA, WO
我们计算了一大类各向异性超导体的频率依赖电导率的吸收部分。杂质散射的影响包括在一个自洽的t-矩阵近似的水平。发现能隙节点在费米面上的任何超导态都有低频吸收（0< Ω< 2Δ）。我们证明了σ（Ω）对杂质浓度的低频依赖性可以帮助确定候选系统（如重电子化合物或高Tc超导体）中序参量的结构。我们还讨论了如何强散射，类似于在普通超导体中观察到的掺杂近藤杂质，可能会导致吸收的阈值为Ω Δ，而不是2Δ在准各向同性系统。最后，我们考虑了序参数集体模对电磁吸收的贡献，并表明这种吸收可能是实质性的，并敏感地依赖于杂质散射率。
We calculate the absorptive part of the frequency-dependent conductivity for a large class of anisotropic superconductors. The effect of nonmagnetic impurity scattering is included at the level of a self-consistent t-matrix approximation. It is found that low-frequency absorption (0< Ω< 2Δ) takes place for any superconducting state with nodes of the energy gap on the Fermi surface. We demonstrate that the limiting low-frequency dependence of σ (Ω) on impurity concentrations can help to determine the structure of the order parameter in candidate systems such as heavy-electron compounds or high-T c superconductors. We also discuss how strong scattering, similar to that observed in ordinary superconductors doped with Kondo impurities, may lead to absorption with a threshold of Ω≃ Δ rather than 2Δ as in quasiisotropic systems. Finally, we consider the contribution of order-parameter collective modes to the electromagnetic absorption, and show that this absorption may be substantial and depends sensitively on the impurity scattering rate.