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arXiv 2201.01317cond-mat.supr-concond-mat.dis-nncond-mat.str-el
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无序s波超导体中的亚能隙双粒子谱权重:来自模式耦合方法的见解

Subgap two-particle spectral weight in disordered $s$-wave superconductors: Insights from mode coupling approach

Prathyush P. Poduval, Abhisek Samanta, Prashant Gupta, Nandini Trivedi, Rajdeep Sensarma

AI总结:

本文通过无序吸引Hubbard模型和解析模式耦合方法,揭示了弱无序s波超导体中亚能隙双粒子谱权重的产生机制及其在Higgs与相位通道间的分布规律。

摘要:

我们利用方晶格上的无序吸引Hubbard模型,研究弱无序超导体的双粒子谱函数和集体模式。我们表明,集体模式之间由无序诱导的散射会在长波极限下产生有限的亚能隙谱权重。一般而言,谱权重分布在相位通道和Higgs通道之间,但随着我们接近半填充,Higgs贡献占据主导。密度涨落的引入降低了该模式出现的频率,并导致相位通道对这一亚能隙模式获得更大的贡献。在半填充附近,系统接近电荷密度波(CDW)不稳定性,导致在公度波矢($[π,π]$)处有效无序的强烈涨落。我们发展了一种解析模式耦合方法,其中长波极限下的纯Goldstone模式与$[π,π]$处的集体模式耦合。这为理解双粒子谱权重在Higgs通道和相位通道之间的位置和分布提供了见解。

英文摘要:

We study the two-particle spectral functions and collective modes of weakly disordered superconductors using a disordered attractive Hubbard model on square lattice. We show that the disorder induced scattering between collective modes leads to a finite subgap spectral weight in the long wavelength limit. In general, the spectral weight is distributed between the phase and the Higgs channels, but as we move towards half-filling the Higgs contribution dominates. The inclusion of the density fluctuations lowers the frequency at which this mode occurs, and results in the phase channel gaining a larger contribution to this subgap mode. Near half-filling, the proximity of the system to the charge density wave (CDW) instability leads to strong fluctuations of the effective disorder at the commensurate wave-vector ($[π,π]$). We develop an analytical mode coupling approach where the pure Goldstone mode in the long wavelength limit couples to the collective mode at $[π,π]$. This provides insight into the location and distribution of the two-particle spectral weights between the Higgs and the phase channels.

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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