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arXiv 2312.08693cond-mat.supr-concond-mat.dis-nncond-mat.mes-hallcond-mat.str-el
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无序薄膜中的量子涨落与多重分形增强超导

Quantum Fluctuations and Multifractally-Enhanced Superconductivity in Disordered Thin Films

E. S. Andriyakhina, P. A. Nosov, S. Raghu, I. S. Burmistrov

AI总结:

本研究针对二维无序薄膜中多重分形增强的超导态,基于Finkel'stein非线性sigma模型推导含量子涨落的有效作用量,得到修正的超导方程并建立其与正常态重整化群方程的关联,为理解超导转变温度增强机制提供理论支撑。

摘要:

二维系统中电子-电子相互作用与弱局域化(或反局域化)现象的相互作用可显著提升超导转变温度。我们构建了薄膜中此类多重分形增强超导态内的量子涨落理论。在弱无序条件下,我们采用Finkel'stein非线性sigma模型,推导了超导序参量与准经典格林函数的有效作用量,细致考量了量子涨落的影响。该有效作用量适用于任意强度的相互作用,揭示了脏超导体中已知集体模式的关键作用,对其进行鞍点分析可得到修正的Usadel方程与能隙方程。这些方程全面纳入了相互作用与无序相互作用带来的重整化效应,导致能隙函数具有非平凡的能量依赖关系。值得注意的是,我们的分析建立了超导转变温度下的自洽能隙方程与正常态相互作用参数的已知重整化群方程之间的直接关联。

英文摘要:

The interplay between electron-electron interactions and weak localization (or anti-localization) phenomena in two-dimensional systems can significantly enhance the superconducting transition temperature. We develop the theory of quantum fluctuations within such multifractally-enhanced superconducting states in thin films. In conditions of weak disorder, we employ the Finkel'stein nonlinear sigma model to derive an effective action for the superconducting order parameter and the quasiclassical Green's function, meticulously accounting for the influence of quantum fluctuations. This effective action, applicable for interactions of any strength, reveals the critical role of well-known collective modes in a dirty superconductor, and its saddle point analysis leads to modified Usadel and gap equations. These equations comprehensively incorporate the renormalizations stemming from the interplay between interactions and disorder, resulting in the non-trivial energy dependence of the gap function. Notably, our analysis establishes a direct relation between the self-consistent gap equation at the superconducting transition temperature and the known renormalization group equations for interaction parameters in the normal state.

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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