标题： 强耦合超导体中的磁杂质 显示英文标题

标题： Magnetic impurities in a strongly coupled superconductor

摘要： 我们重新审视了金属中由磁性杂质引起的载流子散射对其超导性质影响的问题的某些方面。 假设超导性是由强电子-声子相互作用驱动的。 我们使用Nagaoka方程的自洽解来计算散射矩阵，并结合Migdal-Eliashberg超导理论来计算能隙内束缚态的能量、超导临界温度和隧穿态密度，适用于Kondo温度和杂质浓度的广泛范围。 发现类似于弱耦合（BCS）超导体的情况，在导带电子与磁性杂质之间存在反铁磁交换耦合的情况下，能隙内只有一对束缚态以及再入超导性。 与早期研究一致，我们发现可以实现无能隙超导性，而在反铁磁交换的情况下，所需的杂质浓度要小得多。 令人惊讶的是，与弱耦合超导体不同，我们发现对于铁磁交换耦合，超导转变表现出两个临界温度。 显示英文摘要

摘要： We revisit certain aspects of a problem concerning the influence of carrier scattering induced by magnetic impurities in metals on their superconducting properties. Superconductivity is assumed to be driven by strong electron-phonon interaction. We use the self-consistent solution of the Nagaoka equations for the scattering matrix together with the Migdal-Eliashberg theory of superconductivity to compute the energy of the in-gap bound states, superconducting critical temperature and tunneling density of states for a wide range of values of the Kondo temperature and impurity concentrations. It is found that similar to the case of the weak coupling (BCS) superconductors there is only one pair of the bound states inside the gap as well as re-entrant superconductivity for the case of antiferromagnetic exchange coupling between the conduction electrons and magnetic impurities. In agreement with the earlier studies we find that the gapless superconductivity can be realized which in the case of antiferromagnetic exchange requires much smaller impurity concentration. Surprisingly, in contrast with the weakly coupled superconductors we find that superconducting transition exhibits two critical temperatures for the ferromagnetic exchange coupling.