论文标题
子仪的两粒子光谱重量为$ s $ - 波超导体：模式耦合方法的见解
Subgap two-particle spectral weight in disordered $s$-wave superconductors: Insights from mode coupling approach
论文作者
论文摘要
我们使用方形晶格上的无序吸引人的哈伯德模型研究了弱小的超导体的两粒子光谱函数和集体模式。我们表明，这种疾病引起的集体模式之间的散射导致长波长极限的有限亚级光谱重量。通常，光谱重量分布在相位和希格斯通道之间，但是当我们朝着半填充希格斯的贡献时，主导着频谱。密度波动的包含降低了此模式发生的频率，并导致相通道对该子段模式产生更大的贡献。接近一半的填充，系统与电荷密度波（CDW）不稳定性的接近性会导致在相应波形矢量（$ [π，π] $）处的有效障碍的强烈波动。我们开发了一种分析模式耦合方法，其中纯波长的纯金矿模式限制了$ [π，π] $的集体模式。这提供了对希格斯和相通道之间两粒子光谱权重的位置和分布的见解。
We study the two-particle spectral functions and collective modes of weakly disordered superconductors using a disordered attractive Hubbard model on square lattice. We show that the disorder induced scattering between collective modes leads to a finite subgap spectral weight in the long wavelength limit. In general, the spectral weight is distributed between the phase and the Higgs channels, but as we move towards half-filling the Higgs contribution dominates. The inclusion of the density fluctuations lowers the frequency at which this mode occurs, and results in the phase channel gaining a larger contribution to this subgap mode. Near half-filling, the proximity of the system to the charge density wave (CDW) instability leads to strong fluctuations of the effective disorder at the commensurate wave-vector ($[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.
