EAGER: SUPER: Light-Induced Room-Temperature Superconductivity at Light Pressure

非技术总结这个热切的奖项支持理论和实验研究，以及利用光诱导和探测超导电性的教育。在传统超导体中，在足够低的温度下，电子形成一个集体量子力学状态，具有不寻常的性质，包括无电阻导电的能力。超导通常在看似极端的条件下发生，要么出现在非常低的温度下，一些常见的气体是液体，要么就像最近证明的轻元素氢基化合物一样，在接近行星核心深处的非常高的压力下出现。然而，激光物理学最近的实验进展表明，光和压力一样，可以充当一种控制材料电子行为的“旋钮”，这表明，在更高的温度或接近环境条件的更适中的压力下，有一种惊人的替代方案可以实现超导。该项目的中心目标是利用定制的光照射来研究和控制超导化合物的电子性质。虽然传统的超导电性在平衡的稳定状态下得到了很好的研究，但超导体中的电子对强外场(如光)的响应仍然知之甚少，并构成了这一理论和实验相结合的工作的主要焦点。该项目包括开发理论模型，以预测轻元素超导体因晶格振动的定向激发而失去平衡的响应。PI将专注于碳和氢材料的类别，即富勒化物和氢化物。一个具体的目标是绘制路径图，以利用这些振动模式作为压力的替代品，驱动从绝缘或金属状态到超导状态的转变。将进行光学光谱测量作为与激光脉冲击中材料的时间同步的时间的函数的实验。了解这些反应有助于指导理论建模，并有助于设计未来一代电子设备。该项目包括除了标准的教授课堂教学之外的几项活动，以及对博士后和学生的指导。PIS正在开发新的课程和新的推广方法，将向STEM学生和普通公众广泛介绍量子材料。特别是第一代大学生将参与研究问题，让他们对超导量子材料的现代研究有一种感觉。技术总结这个热切的奖项集中在利用光在轻元素量子材料中诱导超导电性。虽然非传统的铜酸盐超导体在常温下保持着最高的超导转变温度纪录，但最近的一系列实验表明，轻元素传统超导体的转变温度很高。范围从富勒化物到氢化物，在压力下具有里程碑式的近室温超导电性。虽然这些材料的超导电性需要极高的压力，但最近对铜酸盐、有机电荷转移盐和氢化物的一系列开创性实验表明，光脉冲照射原则上可以提供一种替代方法来诱导长寿命的超导信号脱离平衡。该项目的目标是从理论和实验上证明，光可以有效地替代外部压力的作用，并在极低的压力和高温下诱导非平衡超导状态。为此，PI将对两类化合物--富勒化物和氢化物--进行理论建模和光泵太赫兹探测实验。对于前者，一个关键的目标是在高温和非平衡的Mott-Jahn-Teller绝缘体中进行光致绝缘体-超导体转变的实验论证和理论描述，重点是通过声子的选择性光激发来模拟外压的作用。对于后者，PI旨在证明氢化物在压力下的光致超导电性。为了实现电子配对的受控增强，PI将从理论和实验上研究这些材料中声子光谱的定向激发和非谐性的作用。这一项目的成功将代表着对远离平衡的量子相的理解的进步，并可能为在环境条件下实现轻元素超导开辟新的研究方向。教育贡献包括教与学活动的整合，使K-12学生和普通公众能够在研究实验室之外看到宏观的量子现象，并提高他们对STEM相关领域的认识。这些活动包括指导博士后和第一代大学本科生，以及与富兰克林研究所科学博物馆合作现场表演演示，并将视频录制到K-12学生的互动虚拟学习编程中。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis EAGER award supports theoretical and experimental research, and education on using light to induce and probe superconductivity. In conventional superconductors at sufficiently low temperature, electrons form a collective quantum mechanical state with unusual properties including the ability to conduct electricity without resistance. Superconductivity typically often occurs under seemingly extreme conditions, appearing either at very low temperatures where some common gases are liquids or, as recently demonstrated for light-element hydrogen-based compounds, under very high pressures approaching those found deep in the core of planets. However, recent experimental advances in laser physics suggest that light, like pressure, can act as a kind of "knob" to control the electronic behavior of materials, suggesting a striking alternative possibility of attaining superconductivity at much higher temperatures or more modest pressures approaching ambient conditions. The central goal of this project is to leverage tailored irradiation with light to study and control electronic properties of superconducting compounds. While conventional superconductivity is well-studied in the steady state of equilibrium, the response of electrons in superconductors to strong external fields such as a light remains less understood and constitutes the main focus of this combined theoretical and experimental effort. This project involves the development of theoretical models to predict the response of light-element superconductors driven out of equilibrium by targeted excitation of crystal lattice vibrations. The PIs will focus on classes of carbon and hydrogen bearing materials known as fullerides and hydrides. A specific aim is to chart pathways to utilize these vibrational modes as a substitute for pressure, to drive transformations from an insulating or metallic states to a superconducting state. Experiments will be performed involving optical spectroscopy measurements as a function of time synchronized to the time the laser pulse hits the material. Understanding the responses could help guide theoretical modeling and help in the design of future generation of electronic devices. This project includes several activities beyond standard professorial classroom teaching and mentoring of postdocs and students. The PIs are working on new course development and new outreach methods that will be a broad introduction of quantum materials to the STEM students and the general public. Particularly, first-generation college undergraduates will be involved in research problem to give them a sense of modern research in superconducting quantum materials.TECHNICAL SUMMARYThis EAGER award focuses on the use of light to induce superconductivity in light-element quantum materials. While unconventional cuprate superconductors hold the record for highest superconducting transition temperature at ambient conditions, a series of recent experiments demonstrated high transition temperatures in light-element conventional superconductors. These range from the fullerides to hydrides with landmark near-room-temperature superconductivity under pressure. While superconductivity in these materials requires extremely high pressures, recently a series of seminal experiments on cuprates, organic charge-transfer salts, and hydrides suggest that irradiation with optical pulses can in principle provide an alternative way to induce long-lived superconducting signatures out of equilibrium.The goal of this project is to demonstrate theoretically and experimentally that light can effectively be a substitute in the role of external pressure and induce a non-equilibrium superconducting state at much reduced pressures and high temperatures. To this end, the PIs will perform theoretical modeling and optical-pump terahertz-probe experiments on two classes of compounds, the fullerides and hydrides. For the former, a key aim is the experimental demonstration and theoretical description of a light-induced insulator-superconductor transition in the Mott-Jahn-Teller insulator out of equilibrium and at elevated temperatures, with emphasis on mimicking the role of external pressure through selective optical excitation of phonons. For the latter, the PIs aim to demonstrate light induced superconductivity in hydrides under pressure. To achieve a controlled enhancement of electronic pairing, the PIs will investigate theoretically and experimentally, targeted excitation of the phonon spectrum in these materials and the role of anharmonicities.The success of this project will represent an advance in the understanding of quantum phases driven far out of equilibrium and may open new research directions towards achieving light-element superconductivity at ambient conditions. Educational contributions include the integration of teaching and learning activities that will enable K-12 students and the general public to see macroscopic quantum phenomena outside of research laboratories and to raise their awareness of the STEM fields involved. These activities include mentoring postdocs and first-generation college undergraduate students, as well as working with the Franklin Institute Science Museum to perform demos onsite and record the videos into interactive virtual learning programming for K-12 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.