Investigation of optically-driven supercondcutors using pump-probe Raman scattering

使用泵浦探针拉曼散射研究光驱动超导体

• 批准号: 2210126
• 负责人: Dmitry Reznik
• 金额: $ 40.62万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210126&HistoricalAwards=false
• 关键词: Investigation; optically; driven; supercondcutors; using

Non-Technical Abstract Superconductivity is characterized by a complete loss of electrical resistance. It is a quantum state that arises out of strong interactions of electronic charges and orbitals, magnetism, and vibrations of atoms. The specific mechanisms in many materials are puzzling to scientists. This project takes advantage of a recently developed experimental technique, pump-probe Raman spectroscopy, to investigate superconductivity in so-called transient states. These occur right after a very short laser pulse hits the material and either kicks some electrons out of their orbits or induces large amplitude vibrations of the atoms. The material can briefly go into a different transient state, e.g., a superconductor will lose superconductivity, or the opposite can happen – superconductivity may arise in a material that does not exhibit it under normal circumstances. Time-resolved Raman scattering creates a movie of how these states develop and how they come back to the original state. The main idea behind this project is to make such movies of superconductors to reveal otherwise hidden quantum processes. This knowledge is used to test ideas about mechanisms of superconductivity and helps to harness superconductors for practical applications. The work is carried out at the ultrafast laser spectroscopy laboratory at the University of Colorado-Boulder built with the funds provided earlier by the National Science Foundation. The project contributes to the education and training of graduate and undergraduate students.Technical AbstractThis project focuses on groundbreaking measurements of superconductors shortly after absorption of an ultrashort laser pulse. The purpose is to experimentally investigate still enigmatic mechanisms of equilibrium superconductivity in copper oxides as well as the general phenomenon of light-induced nonequilibrium superconductivity. In the experiments, the investigated sample is driven out of equilibrium by a short laser pulse, and Raman scattering from another time-delayed pulse will probe its relaxation. These experiments track time-evolution of phonons, electronic temperature, and the superconducting gap as the system thermalizes. This novel approach elucidates energy flows, transient timescales, and heating in optically-driven superconductivity recently reported in intercalated C60 and some copper oxides. Nonlinear phononics and Josephson current-based mechanisms suggested as explanations of this phenomenon are tested. Advances in this area will ultimately underlie development of new materials and devices involving optical control of superconductivity. The work is carried out at the ultrafast laser spectroscopy laboratory at the University of Colorado-Boulder built with the funds provided previously by National Science Foundation. The project contributes to the education and training of graduate and undergraduate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术抽象的超导性的特征是完全丧失电阻。这是一个量子状态，它是由电子电荷和轨道，磁性和原子振动的强相互作用引起的。许多材料中的具体机制都对科学家感到困惑。该项目利用了最近开发的实验技术泵探针拉曼光谱，以研究所谓的瞬态状态的超导性。这些发生在非常短的激光脉冲击中材料后，然后将某些电子从轨道踢出来，或者诱导原子的大放大器振动。该材料可以短暂地进入不同的瞬态状态，例如，超导体会失去超导性，或者可能发生相反的情况 - 在正常情况下不存在的材料中可能会出现超导性。时间分辨的拉曼散射创作了一部电影，讲述了这些状态如何发展以及它们如何回到原始状态。该项目背后的主要思想是制作超导体的这样的电影，以揭示其他隐藏的量子过程。这些知识用于测试有关超导体机制的想法，并有助于利用超导体进行实际应用。这项工作是在科罗拉多大学的超快激光光谱实验室进行的，该实验室由国家科学基金会前面提供的资金建造。该项目为研究生和本科生的教育和培训做出了贡献。技术摘要该项目重点介绍了超时激光脉冲痛苦后不久的超导体的开创性测量。目的是实验研究铜氧化物中平衡超导性的神秘机制以及光诱导的非平衡超导性的一般现象。在实验中，所研究的样品通过短激光脉冲从平衡中驱动，而拉曼从另一个延迟的脉冲中散射将探测其松弛。这些实验会跟踪声子，电子温度和系统热量差异的时间进化。这种新颖的方法阐明了在插入的C60和一些铜氧化物最近报道的光学驱动的超导性中的能量流，瞬时时间标准和加热。测试了该现象的解释的非线性语音和Josephson电流机制。该领域的进步最终将是涉及超导性光控制的新材料和设备的开发。这项工作是在科罗拉多大学的超快激光光谱实验室进行的，该实验室由国家科学基金会先前提供的资金建造。该项目为研究生和本科生的教育和培训做出了贡献。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准来诚实地通过评估来诚实地支持。