超导涨落对非互易二向色性和旋光性的影响
Effect of superconducting fluctuations on nonreciprocal dichroism and gyrotropy
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中文总结 AI 辅助
研究二维非中心对称超导体空间色散电导率，利用含时金兹堡 - 朗道理论计算其对旋光电导率的阿斯拉马佐夫 - 拉金贡献，分析非互易二向色性和旋光双折射特性及影响，探讨在相关材料中探测超导动力学的意义。
中文摘要 AI 辅助
我们研究了二维非中心对称超导体的空间色散电导率，表明在临界温度\(T_c\)以上，它从涨落诱导的库珀对中获得了一个非互易的、波矢为奇数的分量。利用广义的含时金兹堡 - 朗道理论，包括粒子 - 空穴不对称性和三角超导体的立方里夫希茨不变量，我们以封闭形式计算了对旋光电导率的阿斯拉马佐夫 - 拉金贡献，包括其完整的频率依赖性。耗散部分描述了非互易方向二向色性，其在频率上为奇数且显示出非单调依赖性，在与涨落库珀对衰减率相当的频率处达到峰值。其克莱默斯 - 克朗尼格对偶分量描述了旋光双折射，在静态极限下保持有限，并且随着温度接近\(T_c\)而强烈增强。这两种效应都需要同时打破空间反演和时间反演对称性，与涨落霍尔效应类似，依赖于粒子 - 空穴不对称性，并追溯到导致超导二极管效应和在\(T_c\)附近观察到的巨磁手性各向异性的相同不对称库珀对色散。这种临界增强在平滑的正常态旋光性之上占主导，我们对相同的能带模型进行评估作为基线。最后，我们在诸如\(MoS_2\)等门控过渡金属二硫属化物的背景下进行分析，讨论通过氮空位中心量子噪声光谱探测超导动力学的意义。
英文摘要
We study the spatially dispersive conductivity of a two-dimensional noncentrosymmetric superconductor, demonstrating that it acquires a nonreciprocal, odd-in-wavevector component from fluctuation-induced Cooper pairs above the critical temperature $T_c$. Utilizing time-dependent Ginzburg-Landau theory generalized to include particle-hole asymmetry and the cubic Lifshitz invariant of trigonal superconductors, we compute the Aslamazov-Larkin contribution to the gyrotropic conductivity in closed form, including its complete frequency dependence. The dissipative part describes nonreciprocal directional dichroism: it is odd in frequency and displays a nonmonotonic dependence, peaking at frequencies comparable to the decay rate of fluctuating Cooper pairs. Its Kramers-Kronig dual component describes gyrotropic birefringence, which remains finite in the static limit and is strongly enhanced as the temperature approaches $T_c$, as long as the probe frequency stays below the pair decay rate. Both effects require simultaneously broken inversion and time-reversal symmetries, are dependent on particle-hole asymmetry in close analogy to the fluctuation Hall effect, and trace to the same asymmetric Cooper-pair dispersion responsible for the superconducting diode effect and the giant magnetochiral anisotropy observed near $T_c$. In this regime this critical enhancement dominates over the smooth normal-state gyrotropy, which we evaluate for the same band model as a baseline. Finally, we frame our analysis within the context of gated transition metal dichalcogenides like MoS$_2$, discussing the implications for probing superconducting dynamics through nitrogen-vacancy-center quantum noise spectroscopy.
发表机构
- University of Wisconsin–Madison（威斯康星大学麦迪逊分校）
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