论文标题
飞秒时域光谱法探测的超导体中的非平衡现象
Non-equilibrium phenomena in superconductors probed by femtosecond time-domain spectroscopy
论文作者
论文摘要
在过去的二十年中，超快激光器和非线性光学技术的开发为访问超导体低能激励的实时动力学提供了工具。例如，时间分辨的THZ光谱以及时间和角度分辨的光发射光谱可访问超导间隙幅度的实时动力学。这样的研究实现了微观参数，例如准粒子重组率，破坏成对速率和电子玻色子耦合常数。最近，强烈的THZ脉冲已被用来探测非线性动力学，包括观察集体模式。此外，使用低频电磁脉冲，在常规和非常规的超导体中都有一些扩增超导性的报道。首先是对开创性工作的简短历史概述，其中使用准连续激发研究了超导体中的非平衡现象，我们回顾了使用实时方法提供的一些见解。我们专注于常规的BCS超导体，其基础状态对其进行了良好的理解，并解决了与High-T $ _ {C} $超导体中相应研究有关的相似性和开放问题。
Development of ultrafast lasers and non-linear optical techniques over the last two decades provides tools to access real-time dynamics of low energy excitations in superconductors. For example, time-resolved THz spectroscopy and time- and angular-resolved photoemission spectroscopy provide access to the real-time dynamics of the superconducting gap amplitude. Such studies enable determination of microscopic parameters like quasi-particle recombination rates, pair-breaking rates and electron-boson coupling constants. Recently, intense THz pulses have been used to probe the non-linear dynamics, including observation of collective modes. Moreover, using low frequency electromagnetic pulses, there are several reports of amplification of superconductivity in both conventional and unconventional superconductors. Starting with a brief historical overview of the pioneering work, where non-equilibrium phenomena in superconductors were investigated using quasi-continuous excitation, we review some of the insights that are provided by using real-time approaches. We focus on conventional BCS superconductors, whose ground state is reasonably well understood, and address similarities and open questions related to the corresponding studies in high-T$_{c}$ superconductors.
