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arXiv 1507.06409cond-mat.str-elcond-mat.quant-gascond-mat.supr-con
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强吸引哈伯德模型超导电性中的隐费米子激发

Hidden fermionic excitation in the superconductivity of the strongly attractive Hubbard model

Shiro Sakai, Marcello Civelli, Yusuke Nomura, Masatoshi Imada

摘要:

本文在动力学平均场论的框架下,研究了引力哈伯德模型超导态自能的实频结构。在文献中根据玻色-爱因斯坦凝聚所理解的强耦合超导相中,我们发现两个性质不同的区域相互交叉。在一个接近零温度的区域,自能在低能量下仅微弱地依赖于频率。另一方面,在接近临界温度的区域中,自能表现出极结构。随着相互作用的加强,后一区域变得更加占主导地位。我们发现,在后一个区域中的自能极产生的耦合到一个隐藏的费米子激发。隐藏的费米子保持在正常状态,在那里它产生一个赝能隙。我们比较这些属性与排斥哈伯德模型相关的高温铜氧化物超导体,隐藏的费米子是一个关键的共同成分强关联超导。

英文摘要:

We scrutinize the real-frequency structure of the self-energy in the superconducting state of the attractive Hubbard model within the dynamical mean-field theory. Within the strong-coupling superconducting phase which has been understood in terms of the Bose-Einstein condensation in the literature, we find two qualitatively different regions crossing over each other. In one region close to zero temperature, the self-energy depends on the frequency only weakly at low energy. On the other hand, in the region close to the critical temperature, the self-energy shows a pole structure. The latter region becomes more dominant as the interaction becomes stronger. We reveal that the self-energy pole in the latter region is generated by a coupling to a hidden fermionic excitation. The hidden fermion persists in the normal state, where it yields a pseudogap. We compare these properties with those of the repulsive Hubbard model relevant for high-temperature cuprate superconductors, showing that hidden fermions are a key common ingredient in strongly correlated superconductivity.

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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