Collaborative Research: Probing quasiparticle excitations in TMDC Moiré superlattices for revealing and understanding novel two-dimensional correlated phases

合作研究：探测 TMDC 莫尔超晶格中的准粒子激发，以揭示和理解新颖的二维相关相

• 批准号: 2104036
• 负责人: Rui He
• 金额: $ 25.78万
• 依托单位: Texas Tech 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: 2021-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104036&HistoricalAwards=false
• 关键词: Collaborative; Research; Probing; quasiparticle; excitations

Non-technical abstract:Thanks to the development of two-dimensional (2D) atomic crystals, researchers have managed to create a new kind of periodic lattice that arises from the interference of two vertically stacked 2D atomic lattices. The existence of this so called "moire superlattice", has been theoretically predicted and experimentally demonstrated. In this collaborative project, the research team studies a family of such moire superlattices made from transition metal dichalcogenides (TMDC). The team aims at understanding the key questions of how semiconducting TMDC monolayers turn into unconventional insulators, magnets, or even superconductors when stacked together vertically, by probing the dynamics of the periodic lattices, the charge carriers, and the magnetic moments in these TMDC stacked structures. The project is further integrated with education and outreach activities to recruit and mentor underrepresented and first-generation students, present demo experiments and tutorials to K-12 students, and introduce the background and results from collaborative research to the general public. These activities involve a wide group of participants and promote science, technology, and engineering among K-12 students and the public.Technical abstract:The formation of moire superlattice by either lattice mismatch or angular misalignment between two atomically thin crystals has been experimentally demonstrated as a powerful way to design and engineer electronic properties of 2D systems. One particular outstanding example is the small twist-angle TMDC moire superlattices, showing a wealth of strongly correlated electronic phases that are absent in the individual composing TMDC monolayers. In this collaborative project, the research goal is to develop a comprehensive understanding on these emergent correlated phases in TMDC moire superlattices. The focus is to investigate the collective phonon, charge, and magnon excitations of these correlated phases by using an integrated optical spectroscopy experiment and first-principles theory method. Specifically, the research team fabricates TMDC moire superlattices, performs time- and frequency-domain dynamic measurements using time-resolved and Raman optical spectroscopy, and carries out theoretical calculations to guide the experimental design and interpret the experimental results. The success of this project not only opens a new pathway to better understand emergent correlated physics in 2D systems, but also expands the platform to explore strongly correlated physics in general.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：由于二维（2D）原子晶体的发展，研究人员成功地创建了一种新型周期晶格，这种周期晶格是由两个垂直堆叠的2D原子晶格的干涉产生的。这种所谓的“莫尔超晶格”的存在已被理论预测和实验证明。在这个合作项目中，研究小组研究了一系列由过渡金属二硫化物（TMDC）制成的莫尔超晶格。该团队旨在通过探索这些 TMDC 堆叠结构中的周期晶格、载流子和磁矩的动力学，了解半导体 TMDC 单层在垂直堆叠在一起时如何转变为非常规绝缘体、磁体甚至超导体的关键问题。该项目进一步与教育和外展活动相结合，以招募和指导代表性不足的学生和第一代学生，向 K-12 学生展示演示实验和教程，并向公众介绍合作研究的背景和结果。这些活动涉及广泛的参与者，并在 K-12 学生和公众中推广科学、技术和工程。技术摘要：通过两个原子薄晶体之间的晶格失配或角度失准形成莫尔超晶格已被实验证明为设计和工程 2D 系统电子特性的强大方法。一个特别突出的例子是小扭转角 TMDC 莫尔超晶格，显示出大量强相关的电子相，而这些电子相在单独的 TMDC 单层结构中是不存在的。在这个合作项目中，研究目标是全面了解 TMDC 莫尔超晶格中出现的相关相。重点是通过使用集成光谱实验和第一性原理理论方法来研究这些相关相的集体声子、电荷和磁振子激发。具体来说，研究团队制作了TMDC莫尔超晶格，利用时间分辨光谱和拉曼光谱进行时域和频域动态测量，并进行理论计算来指导实验设计和解释实验结果。该项目的成功不仅为更好地理解二维系统中的新兴相关物理开辟了一条新途径，而且还扩展了探索一般强相关物理的平台。该奖项反映了 NSF 的法定使命，并通过使用评估来认为值得支持基金会的智力价值和更广泛的影响审查标准。

项目成果

Evidence for Topological Magnon–Phonon Hybridization in a 2D Antiferromagnet down to the Monolayer Limit

二维反铁磁体中拓扑磁子-声子杂交低至单层极限的证据

• DOI: 10.1021/acs.nanolett.3c00351
• 发表时间: 2023-03
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Luo, Jiaming;Li, Shuyi;Ye, Zhipeng;Xu, Rui;Yan, Han;Zhang, Junjie;Ye, Gaihua;Chen, Lebing;Hu, Ding;Teng, Xiaokun;et al
• 通讯作者: et al

Magnons and magnetic fluctuations in atomically thin MnBi2Te4

原子薄 MnBi2Te4 中的磁振子和磁涨落

• DOI: 10.1038/s41467-022-29996-w
• 发表时间: 2022-12
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Lujan, David;Choe, Jeongheon;Rodriguez;Ye, Zhipeng;Leonardo, Aritz;Nunley, T. Nathan;Chang, Liang;Lee, Shang;Yan, Jiaqiang;Fiete, Gregory A.;et al
• 通讯作者: et al

Magnetic anisotropy reversal driven by structural symmetry-breaking in monolayer α-RuCl3

单层α-RuCl3中结构对称性破缺驱动的磁各向异性反转

• DOI: 10.1038/s41563-022-01401-3
• 发表时间: 2023-01
• 期刊: Nature Materials
• 影响因子: 41.2
• 作者: Yang, Bowen;Goh, Yin Min;Sung, Suk Hyun;Ye, Gaihua;Biswas, Sananda;Kaib, David A.;Dhakal, Ramesh;Yan, Shaohua;Li, Chenghe;Jiang, Shengwei;et al
• 通讯作者: et al