CAREER: Exciton-Phonon Coupling in Quantum Materials: Atomistic Insight for Defects and 2D Materials

职业：量子材料中的激子-声子耦合：缺陷和二维材料的原子洞察

• 批准号: 2144317
• 负责人: David Strubbe
• 金额: $ 55.01万
• 依托单位: University of California - Merced
• 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: 2022-05-01 至 2027-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2144317&HistoricalAwards=false
• 关键词: CAREER; Exciton; Phonon; Coupling; Quantum

This award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2).NONTECHNICAL SUMMARYThis award supports theoretical and computational research and education activities aimed at improving fundamental understanding of the interaction of light and collective vibrations of atoms in materials. This interaction is important in many different phenomena such as changes in atomic structure after absorption of light or the changes in the energy of light due to interaction with atomic vibrations. These interactions are particularly significant when electrons and holes (the empty states left behind by excited electrons) are strongly bound. Such cases include atomically thin two-dimensional (2D) materials, and defects in materials where atoms are missing or added, which can also have unpaired electron spins that are difficult to handle theoretically. This project will develop more accurate and efficient quantum-mechanical computational methods to study interactions of light and vibrations, which will be validated by experimental measurements. The PI will then apply these methods to better understand phenomena in 2D materials and defects, allowing better predictions of which defects are promising for applications in quantum computing, and enabling identification of the elusive atomic structures of defects in 2D materials. The research in this project will benefit society and economic development by building the fundamental scientific knowledge for the advancement of quantum technologies including computing, communication, and sensing. The methods developed will be made available for wide use in the condensed matter theory community by implementation and release in open-source codes, and students and postdocs will be trained in best practices for code development. This project will also innovate in undergraduate education by introducing a Course-based Undergraduate Research Experience as a lab activity into the sophomore-level Modern Physics class at the University of California, Merced. The activity will teach students the role of computation in physics and show applications in current research. The template, evaluation data, and results of this activity will be disseminated in papers and presentations, to enable use in similar classes elsewhere.TECHNICAL SUMMARY This award supports theoretical and computational research and education activities aimed at improving fundamental understanding of exciton-phonon interactions in materials. Important experimentally measured phenomena involving exciton-phonon interactions include ultrafast motions after light absorption, resonant Raman spectroscopy, and vibronic features in optical spectra. In these phenomena, neglect of excitonic effects can give qualitatively different results, but exciton-phonon coupling has not been studied in detail theoretically due to lack of suitable approaches. Exciton-phonon coupling is generally strong in defects and two-dimensional (2D) materials, which are of great interest for quantum applications. Excitingly, developments in first-principles theory and massively parallel computation are now enabling accurate and efficient calculations of forces in the excited state for materials, via the GW approximation and Bethe-Salpeter equation. This project will develop and implement approaches for resonant Raman and vibronic spectra with excitonic effects, which will be applied to study 2D materials and defects for quantum information, including those with challenging triplet ground states. Collaboration with two experimental groups will validate and apply findings from this project. The research in this project will benefit society and economic development by building the fundamental scientific knowledge for the advancement of quantum technologies including computing, communication, and sensing. The methods developed will be made available for wide use in the condensed matter theory community by implementation and release in open-source codes, and students and postdocs will be trained in best practices for code development. This project will also innovate in undergraduate education by introducing a Course-based Undergraduate Research Experience as a lab activity into the sophomore-level Modern Physics class at the University of California, Merced. The activity will teach students the role of computation in physics and show applications in current research. The template, evaluation data, and results of this activity will be disseminated in papers and presentations, to enable use in similar classes elsewhere.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.

该奖项的部分资金来源是《2021 年美国救援计划法案》（公法 117-2）。非技术摘要该奖项支持理论和计算研究及教育活动，旨在提高对光与材料中原子集体振动相互作用的基本理解。这种相互作用在许多不同的现象中都很重要，例如吸收光后原子结构的变化或由于与原子振动相互作用而引起的光能量的变化。当电子和空穴（激发电子留下的空态）紧密结合时，这些相互作用尤其重要。此类情况包括原子薄的二维 (2D) 材料，以及材料中原子缺失或添加的缺陷，这些缺陷也可能具有理论上难以处理的不成对电子自旋。该项目将开发更准确、更高效的量子力学计算方法来研究光和振动的相互作用，并通过实验测量进行验证。然后，PI 将应用这些方法来更好地理解 2D 材料和缺陷中的现象，从而更好地预测哪些缺陷有希望在量子计算中应用，并能够识别 2D 材料中难以捉摸的缺陷原子结构。该项目的研究将为计算、通信和传感等量子技术的进步建立基础科学知识，从而造福社会和经济发展。所开发的方法将通过开源代码的实施和发布在凝聚态理论社区中广泛使用，学生和博士后将接受代码开发最佳实践的培训。该项目还将通过将基于课程的本科生研究体验作为实验室活动引入加州大学默塞德分校二年级现代物理课程，对本科生教育进行创新。该活动将向学生讲授计算在物理学中的作用，并展示计算在当前研究中的应用。本活动的模板、评估数据和结果将在论文和演示文稿中传播，以便在其他地方的类似课程中使用。技术摘要该奖项支持旨在提高对激子-声子相互作用的基本理解的理论和计算研究及教育活动材料。涉及激子-声子相互作用的重要实验测量现象包括光吸收后的超快运动、共振拉曼光谱和光谱中的电子振动特征。在这些现象中，忽略激子效应可能会产生性质不同的结果，但由于缺乏合适的方法，激子-声子耦合尚未在理论上进行详细研究。激子-声子耦合在缺陷和二维 (2D) 材料中通常很强，这对量子应用非常感兴趣。令人兴奋的是，第一原理理论和大规模并行计算的发展现在可以通过 GW 近似和 Bethe-Salpeter 方程准确有效地计算材料激发态的力。该项目将开发和实施具有激子效应的共振拉曼和电子振动光谱方法，这些方法将应用于研究二维材料和量子信息缺陷，包括那些具有挑战性的三线态基态。与两个实验小组的合作将验证并应用该项目的研究结果。该项目的研究将为计算、通信和传感等量子技术的进步建立基础科学知识，从而造福社会和经济发展。所开发的方法将通过开源代码的实施和发布在凝聚态理论社区中广泛使用，学生和博士后将接受代码开发最佳实践的培训。该项目还将通过将基于课程的本科生研究体验作为实验室活动引入加州大学默塞德分校二年级现代物理课程，对本科生教育进行创新。该活动将向学生讲授计算在物理学中的作用，并展示计算在当前研究中的应用。该活动的模板、评估数据和结果将在论文和演示文稿中传播，以便在其他地方的类似课程中使用。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响进行评估，被认为值得支持审查标准。