EAGER: BRAIDING: Majorana modes in monolayer topological insulator WTe2

渴望：编织：单层拓扑绝缘体 WTe2 中的马约拉纳模式

• 批准号: 1836697
• 负责人: David Cobden
• 金额: $ 29.9万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1836697&HistoricalAwards=false
• 关键词: EAGER; BRAIDING; Majorana; modes; monolayer

Nontechnical Abstract: Finding alternative paths to quantum computing is paramount at this time, and current approaches face many hurdles. The biggest is decoherence of the qubits, meaning that the quantum information content decays exponentially with time. In principle, decoherence can be avoided using "topological protection". The only realistic known scheme for topological protection is based on creating the qubits from so-called Majorana modes, which are peculiar states that occur at the ends of certain types of quantum wires. One way to make Majoranas is using the special quantum wire that exists at the edge of a topological insulator. The PI, an experimentalist, recently discovered the first natural monolayer two-dimensional (2D) topological insulator, suggesting the possibility to create and manipulate Majoranas in 2D materials. The co-PI is a theorist and expert on topological phenomena; in this project they collaborate to find the simplest way to create and detect Majoranas in this system. The work supports graduate students in topical interdisciplinary work where theory and experiment go hand in hand, and which could conceivably give birth to the next information revolution. The project forms a bridge between the University of Washington, which has a leading research effort in 2D materials, and local industry (including Microsoft) which is investing heavily in applications of quantum computers.Technical: This project aims to establish the viability of the 2D materials platform for creating Majorana zero modes that could be used for topological quantum processing. The team employs monolayer WTe2 as a 2D topological insulator, combined with a 2D superconductor (NbSe2 or FeSe) and a 2D magnet (CrI3 or CrBr3). These materials are stacked into a van der Waals heterostructure along with electrical contacts and tunnel barriers. At the point where the three materials meet a Majorana mode may appear at low temperatures and can be probed by tunneling measurements. This 2D platform offers advantages compared with other Majorana systems including that no magnetic field is required to produce the helical mode, and the possibility to avoid delicate tuning of the chemical potential. The complexity of the many-electron and topological physics involved, and the novelty of the system, calls for close cooperation between experiment and theory. Specific goals are to induce and understand a superconducting proximity gap in the helical edge of WTe2, and to design and test the simplest 2D possible heterostructure devices in which Majoranas may occur and be detected.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：目前找到量子计算的替代途径至关重要，当前的方法面临许多障碍。最大的是量子位的变形，这意味着量子信息内容随时间呈指数衰减。原则上，可以使用“拓扑保护”来避免使用破裂。唯一的拓扑保护方案是基于从所谓的Majorana模式创建量子的，这些模式是在某些类型的量子线末端发生的特殊状态。制作Maporanas的一种方法是使用在拓扑绝缘子边缘存在的特殊量子线。 PI是一名实验研究员，最近发现了第一个天然的单层二维（2D）拓扑绝缘子，这表明有可能在2D材料中创建和操纵Maporanas。 Co-Pi是拓扑现象的理论家和专家。在这个项目中，他们合作寻找最简单的方法来创建和检测该系统中的Maporanas。这项工作为局部跨学科工作的研究生提供了支持，理论和实验齐头并进，并且可以想象，这可能会诞生下一个信息革命。该项目构成了华盛顿大学（University of Washington）之间的桥梁，该项目在2D材料方面具有领先的研究工作，而本地行业（包括微软）正在大量投资于量子计算机的应用。技术：该项目旨在建立2D材料平台用于创建可用于拓扑量化处理的Majorana Zero模式的可行性。该团队使用单层WTE2作为2D拓扑绝缘子，并与2D超导体（NBSE2或FESE）和2D磁铁（CRI3或CRBR3）结合使用。这些材料与电触点和隧道屏障一起堆叠在范德华异质结构中。在三种材料相遇的点上，Majorana模式可能会在低温下出现，并且可以通过隧道测量来探测。与其他Majorana系统相比，这个2D平台具有优势，包括生产螺旋模式不需要磁场，并且有可能避免对化学电位进行微妙的调整。许多电子和拓扑物理学的复杂性以及系统的新颖性要求实验与理论之间进行密切合作。具体的目标是诱导和理解WTE2螺旋边缘的超导接近差距，并设计和测试可能发生Mapoaranas并检测到的最简单的2D可能的异质结构设备。该奖项反映了NSF的法规任务，并认为通过基金会的知识优点和广泛的criter scritia criters criter criter criter criter criteria criter criter criter criter criter criter critia criter criteria criter critia criteria criter critia criteria criter critia criter critia criteria criteria均值得一提。

项目成果

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

• DOI: 10.1103/physrevx.11.041034
• 发表时间: 2020-10
• 期刊: Physical Review X
• 影响因子: 12.5
• 作者: Wenxuan Zhao;E. Runburg;Z. Fei;J. Mutch;P. Malinowski;Bosong Sun;Xiong Huang;D. Pesin

Magnetic proximity and nonreciprocal current switching in a monolayer WTe2 helical edge

• DOI: 10.1038/s41563-020-0620-0
• 发表时间: 2020-01
• 期刊: Nature Materials
• 影响因子: 41.2
• 作者: Wenjin Zhao;Z. Fei;Tiancheng Song;Han Kyou Choi;T. Palomaki;Bosong Sun;P. Malinowski;M. McGuire;J. Chu;Xiaodong Xu;D. Cobden

Evidence for equilibrium exciton condensation in monolayer WTe2

• DOI: 10.1038/s41567-021-01427-5
• 发表时间: 2021-12-23
• 期刊: NATURE PHYSICS
• 影响因子: 19.6
• 作者: Sun, Bosong;Zhao, Wenjin;Cobden, David H.
• 通讯作者: Cobden, David H.