Investigation of topological electronic states in atomic layered materials and heterostructures

原子层状材料和异质结构中的拓扑电子态研究

• 批准号: 2004701
• 负责人: Yongtao Cui
• 金额: $ 34万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004701&HistoricalAwards=false
• 关键词: Investigation; topological; electronic; states; atomic

Non-technical Abstract:Conventional conductors and insulators are distinguished by their abilities to conduct electricity. Topological insulators are a new class of materials which combine an insulating interior with conducting surfaces. Their unique electronic properties can enable new generation of quantum technology such as quantum computers and energy efficient electronics. A recently discovered material, WTe2, exhibits such topological behavior in a single layer form. In this 2D topological insulator system, electrical current can only flow along the edges of the sample. This project investigates the electrical properties both in the interior bulk and at edges of monolayer WTe2, aiming to understand the connection between the topological bulk states and the conducting edges and to develop new methods to manipulate these properties by stacking monolayer WTe2 on other 2D materials. The research team also builds an experimental workflow to effectively screen candidate topological materials predicted by theory, which could potentially lead to discovery of new 2D topological systems. The project is integrated with education activities to attract undergraduate students to research and train them in advanced electronics hardware and development of new instrumentation.Technical Abstract:This project aims to investigate topological physics in 2D systems based on atomic layered materials, with a focus on a recently discovered 2D topological insulator, monolayer WTe2. The research employs a range of electrical characterization techniques to probe the electronic properties of the topological states, including local conductivity by microwave impedance microscopy, chemical potential by electrostatic force microscopy, and thermodynamic density of states by quantum capacitance measurement. The goal is to understand the nature of the bulk electronic states including the effect of interaction on the topological properties. The project also explores heterostructures of monolayer WTe2 with other 2D materials in order to manipulate the topological properties in monolayer WTe2. The research team further develops an effective experimental method to screen candidate materials that are predicted to be 2D topological insulators. The approach involves integration of fabrication and characterization techniques suitable for the study of air-sensitive materials and develops a workflow that minimizes sample fabrication to enhance throughput. Graduate and undergraduate students are involved in the development of the experimental methods which provides a comprehensive training in device fabrication, instrumentation design, and data analysis.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：传统导体和绝缘体的区别在于其导电能力。拓扑绝缘体是一类新型材料，它将绝缘内部与导电表面结合在一起。它们独特的电子特性可以实现新一代量子技术，例如量子计算机和节能电子产品。最近发现的一种材料，WTe2，以单层形式表现出这种拓扑行为。在这个二维拓扑绝缘体系统中，电流只能沿着样品的边缘流动。该项目研究了单层 WTe2 的内部体和边缘的电特性，旨在了解拓扑体状态和导电边缘之间的联系，并开发通过在其他二维材料上堆叠单层 WTe2 来操纵这些特性的新方法。研究团队还建立了一个实验工作流程，以有效筛选理论预测的候选拓扑材料，这可能会导致新的二维拓扑系统的发现。该项目与教育活动相结合，吸引本科生研究和培训他们先进的电子硬件和新型仪器的开发。技术摘要：该项目旨在研究基于原子层状材料的二维系统中的拓扑物理，重点是最近发现了二维拓扑绝缘体，单层WTe2。该研究采用了一系列电表征技术来探测拓扑态的电子特性，包括通过微波阻抗显微镜测量局部电导率、通过静电力显微镜测量化学势以及通过量子电容测量测量状态热力学密度。目标是了解体电子态的性质，包括相互作用对拓扑性质的影响。该项目还探索单层 WTe2 与其他二维材料的异质结构，以操纵单层 WTe2 的拓扑特性。研究团队进一步开发了一种有效的实验方法来筛选预计为二维拓扑绝缘体的候选材料。该方法涉及适合空气敏感材料研究的制造和表征技术的集成，并开发了一个工作流程，可最大限度地减少样品制造以提高通量。研究生和本科生参与实验方法的开发，提供设备制造、仪器设计和数据分析方面的全面培训。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数据进行评估，认为值得支持。更广泛的影响审查标准。

项目成果

Imaging Dual-Moiré Lattices in Twisted Bilayer Graphene Aligned on Hexagonal Boron Nitride Using Microwave Impedance Microscopy

使用微波阻抗显微镜对六方氮化硼上排列的扭曲双层石墨烯中的双莫尔晶格进行成像

• DOI: 10.1021/acs.nanolett.1c00601
• 发表时间: 2021-05
• 期刊: Nano Letters
• 影响因子: 10.8
• 作者: Huang, Xiong;Chen, Lingxiu;Tang, Shujie;Jiang, Chengxin;Chen, Chen;Wang, Huishan;Shen, Zhi;Wang, Haomin;Cui, Yong
• 通讯作者: Cui, Yong

Evidence for equilibrium exciton condensation in monolayer WTe2

单层 WTe2 中平衡激子凝聚的证据

• DOI: 10.1038/s41567-021-01427-5
• 发表时间: 2022-01
• 期刊: Nature Physics
• 影响因子: 19.6
• 作者: Sun, Bosong;Zhao, Wenjin;Palomaki, Tauno;Fei, Zaiyao;Runburg, Elliott;Malinowski, Paul;Huang, Xiong;Cenker, John;Cui, Yong;Chu, Jiun;et al
• 通讯作者: et al

Strong interaction between interlayer excitons and correlated electrons in WSe2/WS2 moiré superlattice

WSe2/WS2莫尔超晶格中层间激子和相关电子之间的强相互作用

• DOI: 10.1038/s41467-021-23732-6
• 发表时间: 2021-12
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Miao, Shengnan;Wang, Tianmeng;Huang, Xiong;Chen, Dongxue;Lian, Zhen;Wang, Chong;Blei, Mark;Taniguchi, Takashi;Watanabe, Kenji;Tongay, Sefaattin;et al
• 通讯作者: et al

Signatures of moiré trions in WSe2/MoSe2 heterobilayers

WSe2/MoSe2 异双层中莫尔三重子的特征

• DOI: 10.1038/s41586-021-03541-z
• 发表时间: 2021-06
• 期刊: Nature
• 影响因子: 64.8
• 作者: Liu, Erfu;Barré, Elyse;van Baren, Jeremiah;Wilson, Matthew;Taniguchi, Takashi;Watanabe, Kenji;Cui, Yong;Gabor, Nathaniel M.;Heinz, Tony F.;Chang, Yia;et al
• 通讯作者: et al

Determination of the Spin Axis in Quantum Spin Hall Insulator Candidate Monolayer WTe2

量子自旋霍尔绝缘体候选单层 WTe2 中自旋轴的确定

• DOI: 10.1103/physrevx.11.041034
• 发表时间: 2021-11
• 期刊: Physical Review X
• 影响因子: 12.5
• 作者: Zhao, Wenjin;Runburg, Elliott;Fei, Zaiyao;Mutch, Joshua;Malinowski, Paul;Sun, Bosong;Huang, Xiong;Pesin, Dmytro;Cui, Yong;Xu, Xiaodong;et al
• 通讯作者: et al