Doping Effects on Excited-State Properties of Two-Dimensional Moiré Crystals

掺杂对二维莫尔晶体激发态特性的影响

• 批准号: 2124934
• 负责人: Li Yang
• 金额: $ 37.5万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2124934&HistoricalAwards=false
• 关键词: Doping; Effects; Excited; State; Properties

NONTECHNICAL SUMMARYThis award supports theoretical and computational research and educational activities that aim to advance the understanding of interactions between electrons in two-dimensional Moire crystals, which are emerging quantum materials formed by stacking two atomic layers with a twisting angle. These twisted structures render a periodic potential that confine electrons and significantly enhance their interactions, giving rise to new electronic and optical properties, such as superconductivity, magnetism, metal/insulator transitions, and highly efficient optical absorption/emission. In this project, the PI plans to efficiently control this confinement effect by adding or extracting electrons from the crystal. Because of the unique two dimensionality of Moire crystals, the PI expects that a small variation in the number of electrons can dramatically tune the confinement potential and subsequently change the electrical conductance, magnetism, and light-matter interactions by orders of magnitude. To accurately calculate these unique electronic interactions, the PI will develop theoretical models and implement them in high-performance simulation packages. The predicted tunable many-electron interactions and electronic and optical properties can potentially lead to the realization of novel electronic devices, programable photon emitters/detectors, and dissipationless electronic states that are promising for energy-efficient quantum-information applications.In addition to the research efforts, this award also supports the training and education of graduate and undergraduate students as the next-generation scientific and engineering workforce. Female and minority students will be recruited to engage in exploring new properties and applications of quantum materials by large-scale simulations. The PI will also develop a simulation-based condensed matter physics course for undergraduate students.TECHNICAL SUMMARYThis award supports an integrated research, education, and outreach program focusing on exploring doping dependent excited-state properties of two-dimensional Moire crystals. The periodic quantum confinement formed by Moire patterns is expected to trap quasiparticles and excitons and to realize arrays of identical quantum dots for programmable transport and optical applications. Moreover, these Moire potentials can enhance van Hove singularities and render unusual many-body physics, such as the Mott insulating phase, Wigner crystals, unconventional superconductivity, exciton condensation, and topological orders. All these desired phenomena and applications are essentially decided by quasiparticles and excitons, which are excited states formed by many-electron interactions. In this project, the PI will calculate the enhanced doping effects on many-electron screening and hence the excited states, functioning as an efficient means of tuning Moire potentials, many-body physics, and topological orders. The PI will develop first-principles many-body perturbation theory methods to capture the coupling between Moire plasmons and excited states for calculating quasiparticles and excitons in doped two-dimensional Moire materials. New opportunities to realize flat exciton bands and exciton insulators by doping narrow-gap topological Moire crystals will also be investigated. In addition to the research efforts, this award also supports the training and education of graduate and undergraduate students as the next-generation scientific and engineering workforce. Female and minority students will be recruited to engage in exploring new properties and applications of quantum materials by large-scale simulations. The PI will also develop a simulation-based condensed matter physics course for 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.

非技术摘要这一奖项支持理论和计算研究和教育活动，旨在促进对二维Moire晶体中电子之间相互作用的理解，这些晶体是通过堆叠两个原子层以扭曲角度堆叠的新兴量子材料。这些扭曲的结构产生了限制电子并显着增强其相互作用的周期性潜力，从而产生了新的电子和光学特性，例如超导性，磁性，金属/绝缘体过渡以及高效的光学吸收/发射/发射。在该项目中，PI计划通过从晶体中添加或提取电子来有效控制这种限制效果。由于Moire晶体的独特二维性，PI期望电子数量的较小变化可以显着调整限制电位，然后通过数量级来改变电导，磁性和光晶状相互作用。为了准确计算这些唯一的电子交互，PI将开发理论模型并在高性能模拟软件包中实现它们。可预测的可调多电子相互作用以及电子和光学特性可能会导致实现新颖的电子设备，可编程的光子发射器/检测器以及无耗散的电子状态，这些国家有望在能源有效的量子信息应用中应用。在研究工作中，该奖项还支持培训和研究生的培训和教育。通过大规模模拟，将招募女学生和少数民族学生来探索量子材料的新物业和应用。 PI还将为本科生开发基于模拟的凝结物理学课程。技术摘要奖支持一项集成的研究，教育和外展计划，专注于探索二维Moire晶体的兴奋剂依赖兴奋性兴奋状态。预计由Moire模式形成的周期性量子限制有望捕获准粒子和激子，并实现可编程运输和光学应用的相同量子点的数组。此外，这些摩尔电势可以增强范霍夫的奇异性和变得异常的多体物理学，例如莫特绝缘阶段，wigner晶体，非常规的超导性，激子凝结和拓扑秩序。所有这些所需的现象和应用基本上都是由准颗粒和激子决定的，这些现象是由许多电子相互作用形成的激发态。在该项目中，PI将计算对多电子筛查的增强掺杂效应，从而使激发态充当调整Moire电位，多体物理学和拓扑顺序的有效手段。 PI将开发第一原理多体扰动理论方法，以捕获Moire等离子体与激发态之间的耦合，以计算掺杂的二维Moire材料中的准粒子和激子。还将研究新的机会，通过掺杂窄间隙拓扑结晶来实现平坦的激子带和激子绝缘子。除了研究工作外，该奖项还支持研究生和本科生作为下一代科学和工程劳动力的培训和教育。通过大规模模拟，将招募女学生和少数民族学生来探索量子材料的新物业和应用。 PI还将为本科生开发基于模拟的凝结物理学课程。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，被认为值得通过评估来支持。

项目成果

Electric field tuning of magnetic states in single magnetic molecules

• DOI: 10.1103/physrevb.106.064405
• 发表时间: 2022-08
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Yan Lu;Yun-Tong Wang;Linghan Zhu;Li Yang;Li Wang

Mechanism of carrier doping induced magnetic phase transitions in two-dimensional materials

• DOI: 10.1103/physrevb.106.205403
• 发表时间: 2022-11
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Yan Lu;Haonan Wang;Li Wang;Li Yang

Multi-meron interactions and statistics in two-dimensional materials

• DOI: 10.1088/1361-648x/ac671c
• 发表时间: 2022-04
• 期刊: Journal of Physics: Condensed Matter
• 作者: Xiaobo Lu;Linghan Zhu;Li Yang

Photoactive Control of Surface-Enhanced Raman Scattering with Reduced Graphene Oxide in Gas Atmosphere

气体气氛中还原氧化石墨烯对表面增强拉曼散射的光活性控制

• DOI: 10.1021/acsnano.1c07695
• 发表时间: 2021
• 期刊: ACS Nano
• 影响因子: 17.1
• 作者: Lu Zhou;Lauren Pusey-Nazzaro;Guanhua Ren;Ligang Chen;Liyuan Liu;Wentao Zhang;Li Yang;Jun Zhou;Jiaguang Han
• 通讯作者: Jiaguang Han