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Reentrant s-wave superconductivity in the periodic Anderson model with attractive conduction band Hubbard interaction
Journal of Physics: Condensed Matter ( IF 2.7 ) Pub Date : 2020-05-13 , DOI: 10.1088/1361-648x/ab83b0
W V van Gerven Oei 1 , D Tanasković
Affiliation  

Spin-flip scattering from magnetic impurities has a strong pair-braking effect in $s$-wave superconductors where increasing the concentration of impurities rapidly destroys superconductivity. For small Kondo temperature $T_K$ the destruction of superconductivity is preceded by the reentrant superconductivity at finite temperature range $T_{c2} < T < T_{c1}$, while the normal phase reappears at $T < T_{c2} \sim T_K$. Here we explore the superconducting phase in a periodic system modeled as the Anderson lattice with additional attractive on-site (Hubbard) interaction $g$ acting on the conduction band electrons. We solve the equations using dynamical mean field theory which incorporates Kondo physics, while the pairing interaction is treated on the static mean-field level. For large coupling $g$ we find reentrant superconductivity which resembles the case with diluted impurities. However, we find evidence that reentrant superconductivity is here not a consequence of many-body correlations leading to the Kondo effect, but it rather stems from a competition between the single-particle hybridization and superconducting pairing. An insight into the spectral functions with in-gap structures is obtained from an approximate noninteracting dual model whose solution interpolates between several exact limits.

中文翻译:

具有吸引力导带哈伯德相互作用的周期性安德森模型中的重入 s 波超导性

来自磁性杂质的自旋翻转散射在 $s$ 波超导体中具有强烈的对制动效应,其中增加杂质浓度会迅速破坏超导性。对于小 Kondo 温度 $T_K$,在有限温度范围 $T_{c2} < T < T_{c1}$ 内,重入超导性先于超导性破坏,而正相在 $T < T_{c2} $T 时重新出现T_K$。在这里,我们探索了模型为安德森晶格的周期系统中的超导相,具有额外的吸引力现场(哈伯德)相互作用 $g$ 作用于导带电子。我们使用结合近藤物理学的动态平均场理论求解方程,而在静态平均场水平上处理配对相互作用。对于大耦合 $g$,我们发现重入超导性类似于稀释杂质的情况。然而,我们发现有证据表明,重入超导性不是导致近藤效应的多体相关性的结果,而是源于单粒子杂交和超导配对之间的竞争。从近似的非相互作用对偶模型中可以深入了解具有带隙结构的谱函数,该模型的解在几个精确限制之间进行插值。
更新日期:2020-05-13
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