DMREF Collaborative Research: Establishing the platform of quasi-one-dimensional topological insulators with emergent functionalities

非技术描述：将拓扑学的概念应用于固态系统，彻底改变了我们对量子现象和材料的理解，并启发了电子、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(TI)是一类材料，它在主体上是电绝缘的，但主体是导电的表面状态。由于受到对称性和拓扑学的保护，这些表面态不受杂质的影响，因此能够从不完美的界面制造出近乎完美的器件，这对传统和量子信息技术都很重要。然而，目前的TI材料存在许多关键挑战，必须在充分发挥其潜力之前加以解决。该项目旨在通过专注于一种新的材料类别--具有紧急功能的准一维(准一维)TIS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家族，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实现拓扑量子计算和低功率自旋电子学提供启示。主要的教育活动将被纳入研究活动，方法是开展公共宣传，培训研究生和本科生，增加代表性不足群体的参与，在这个团队中有两名女性担任领导职务，为物理学和材料科学提供新的面孔，并向技术界和普通公众开放获取研究和教育成果。尽管表面Dirac锥丰富，但在显示其决定性性质和实现TIS的全部前景方面存在根本障碍和限制，例如表面Dirac锥限制在特定的解理平面、弱的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。该项目的目标包括设计和优化准一维TI候选材料，合成和表征，通过应变和温度调节拓扑相变，以及在准一维材料的原子薄层中寻找2D TI。通过在理论和计算、材料合成、自旋和角度分辨光电子能谱、纳米制造、量子传输以及中子和X射线散射方面的互补专业知识和共同努力，该项目有望发现新的TiS、相和现象，控制拓扑转变，实现优越的功能和促进量子技术。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.