arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.04373cond-mat.supr-concond-mat.str-el
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混合价相关金属中的$(s+id)$配对理论

Theory of $(s+id)$ pairing in mixed-valent correlated metals

Emilian M. Nica, Onur Erten

摘要:

最近发现的超导电性的方形平面镍酸盐以及长期困惑的实验在重费米子超导体的动机,我们研究库珀配对之间的相关$d$ -电子耦合到一个带的弱关联电子。我们进行自洽大N计算的有效$t-J$模型的$d$ -电子与额外的杂交。与以往的研究不同的混合价系统,我们专注于参数制度,其中两个杂化带是相关的,以确定配对对称性。对于足够强的杂交,我们发现一个强大的$s+id$配对,打破时间反转和点群对称性的混合价制度。我们的结果说明了如何本质上多带系统,如重费米子可以支持一些高度非平凡的配对状态。他们还提供了一个假定的微观实现以前的唯象建议的$s+id$配对,并提出了一个潜在的解决方案,令人困惑的实验中重费米子超导体,如U $_{1-x}$ Th $_x$ Be $_{13}$,表现出两个超导相变和一个完整的间隙在较低的温度。

英文摘要:

Motivated by the recent discovery of superconductivity in square-planar nickelates as well as by longstanding puzzling experiments in heavy-fermion superconductors, we study Cooper pairing between correlated $d$-electrons coupled to a band of weakly-correlated electrons. We perform self-consistent large N calculations on an effective $t-J$ model for the $d$-electrons with additional hybridization. Unlike previous studies of mixed-valent systems, we focus on parameter regimes where both hybridized bands are relevant to determining the pairing symmetry. For sufficiently strong hybridization, we find a robust $s+id$ pairing which breaks time-reversal and point-group symmetries in the mixed-valent regime. Our results illustrate how intrinsically multi-band systems such as heavy-fermions can support a number of highly non-trivial pairing states. They also provide a putative microscopic realization of previous phenomenological proposals of $s+id$ pairing and suggest a potential resolution to puzzling experiments in heavy-fermion superconductors such as U$_{1-x}$Th$_x$Be$_{13}$ which exhibit two superconducting phase transitions and a full gap at lower temperatures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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