DMREF Collaborative Research: Establishing the Platform of Quasi-one-dimensional Topological Insulators with Emergent Functionalities

DMREF合作研究：建立具有突发功能的准一维拓扑绝缘体平台

• 批准号: 1921581
• 负责人: Fan Zhang
• 金额: $ 70万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921581&HistoricalAwards=false
• 关键词: DMREF; Collaborative; Research; Establishing; Platform

Non-technical Description: Applying the concept of topology to solid state systems has revolutionized our understanding of quantum phenomena and materials, and inspired the design of new functionalities in electronic, atomic, photonic, mechanical, and acoustic systems. For instance, topological insulators (TIs) are a class of materials that are electrically insulating in the bulk, but host conductive surface states. Protected by symmetry and topology, these surface states are immune to impurities and thus enable making near-perfect devices from imperfect interfaces, which are important for both conventional and quantum information technology. However, there exist a number of critical challenges in current TI materials that must be addressed before realizing their full potential. This project aims at overcoming these challenges by focusing on a new class of materials, quasi-one-dimensional (quasi-1D) TIs with emergent functionalities. An iterative loop of theoretical modeling and prediction, material synthesis, and characterization will be established to discover different families of quasi-1D TIs and explore their unique properties for topological phenomena and functionalities. The project's success will shed light on the realization of topological quantum computing and low-power spintronics for next-generation information technology and sustainable energy solutions. Major educational activities will be integrated into the research activities by performing public outreach, training graduate and undergraduate students, increasing participation of under-represented groups, providing a new face to physics and materials science with two women in leadership positions on this team, and offering open access to research and education outputs to the technical community and general public.Technical Description: To date, most of the identified TIs are either strongly bonded bulk materials or layered van der Waals materials. Despite their richness, fundamental obstacles and limitations exist in exhibiting the decisive properties and realizing the full promise of TIs, such as the restriction of surface Dirac cones to a specific cleavage plane, weak electronic interactions and limited tunability. Remarkably, a quasi-1D structure promises to overcome these challenges. The goals of this project include design and optimization of quasi-1D TI candidates, synthesis and characterization, tuning topological phase transitions by strain and temperature, and seeking 2D TIs in atomically thin layers of quasi-1D materials. Through complementary expertise and concerted efforts on theory and computation, material synthesis, spin- and angle-resolved photoemission spectroscopy, nanofabrication, quantum transport, and neutron and x-ray scattering, the project is expected to lead to the discovery of novel TIs, phases and phenomena, controlling topological transitions, and enabling superior functionalities and fostering quantum technologies.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.

非技术描述：将拓扑概念应用于固态系统已经彻底改变了我们对量子现象和材料的理解，并激发了电子、原子、光子、机械和声学系统中新功能的设计。例如，拓扑绝缘体（TIs）是一类在整体上是电绝缘的材料，但具有导电表面状态。在对称和拓扑结构的保护下，这些表面状态不受杂质的影响，因此可以从不完美的界面制造出近乎完美的设备，这对传统和量子信息技术都很重要。然而，在实现其全部潜力之前，当前TI材料存在许多关键挑战，必须加以解决。该项目旨在通过关注一类具有紧急功能的准一维（准1d） ti来克服这些挑战。将建立一个理论建模和预测、材料合成和表征的迭代循环，以发现不同的准一维ti族，并探索它们在拓扑现象和功能方面的独特性质。该项目的成功将为下一代信息技术和可持续能源解决方案的拓扑量子计算和低功耗自旋电子学的实现提供启示。主要的教育活动将通过以下方式纳入研究活动：进行公共宣传、培训研究生和本科生、增加代表性不足群体的参与、为物理学和材料科学提供新面孔（该小组中有两名妇女担任领导职务）以及向技术界和一般公众开放获取研究和教育成果。技术描述：迄今为止，大多数已确定的ti要么是强粘结块状材料，要么是层状范德华材料。尽管具有丰富的性质，但在展示ti的决定性性质和实现ti的全部前景方面存在着基本的障碍和限制，例如表面狄拉克锥限制在特定的解理面，弱电子相互作用和有限的可调性。值得注意的是，准一维结构有望克服这些挑战。该项目的目标包括准一维TI候选材料的设计和优化，合成和表征，通过应变和温度调整拓扑相变，以及在准一维材料的原子薄层中寻找二维TI。通过在理论和计算、材料合成、自旋和角度分辨光谱学、纳米制造、量子输运、中子和x射线散射等方面的互补专业知识和协同努力，该项目有望发现新的ti、相和现象、控制拓扑跃迁、实现卓越的功能和促进量子技术。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Uncovering Topological Edge States in Twisted Bilayer Graphene

揭示扭曲双层石墨烯中的拓扑边缘态

• DOI: 10.1021/acs.nanolett.2c01481
• 发表时间: 2022
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Fortin-Deschênes, Matthieu;Pu, Rui;Zhou, Yan-Feng;Ma, Chao;Cheung, Patrick;Watanabe, Kenji;Taniguchi, Takashi;Zhang, Fan;Du, Xu;Xia, Fengnian
• 通讯作者: Xia, Fengnian

Impact of Electric Field Disorder on Broken-Symmetry States in Ultraclean Bilayer Graphene

电场无序对超净双层石墨烯破缺对称态的影响

• DOI: 10.1021/acs.nanolett.2c02119
• 发表时间: 2022
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Geisenhof, Fabian R.;Winterer, Felix;Seiler, Anna M.;Lenz, Jakob;Zhang, Fan;Weitz, R. Thomas
• 通讯作者: Weitz, R. Thomas

Evidence for Dirac flat band superconductivity enabled by quantum geometry

• DOI: 10.1038/s41586-022-05576-2
• 发表时间: 2023-02
• 期刊: Nature
• 影响因子: 64.8
• 作者: Haidong Tian;Xue-Jian Gao;Yuxin Zhang;S. Che;Tianyi Xu;Patrick Cheung;Kenji Watanabe;T. Taniguchi;M. Randeria;Fan Zhang;C. N. Lau;M. Bockrath

New layered quaternary BaCu6Sn2As4−x and BaCu6Sn2P4−x phases: Crystal growth and physical properties

• DOI: 10.1016/j.jallcom.2021.162111
• 发表时间: 2022
• 期刊: Journal of Alloys and Compounds
• 影响因子: 6.2
• 作者: Hanlin Wu;Sheng Li;Xiqu Wang;Sunah Kwon;Wenhao Liu;Gareth A. Ofenstein;Moon J. Kim;B. Lv

Unconventional valley-dependent optical selection rules and landau level mixing in bilayer graphene

• DOI: 10.1038/s41467-020-16844-y
• 发表时间: 2020-06
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: L. Ju;Lei Wang;Xiao Li;S. Moon;M. Ozerov;Zhengguang Lu;T. Taniguchi;Kenji Watanabe;E. Mueller;Fan Zhang;D. Smirnov;F. Rana;P. McEuen