DMREF: Collaborative Research: The Search for Novel Superconductors in Moire Flat Bands

非技术描述：这个项目将研究基于原子薄材料的新型非传统超导体，这些材料之间堆叠着一个扭曲的角度。当两个原子结构相似的原子层相遇时，形成了一种更大尺度的准周期结构，称为莫尔图案。这些界面结构的电子结构可以通过调整扭转角度来设计。当电子能量分布较窄时，它们之间会出现很强的关联，从而使系统成为无耗散的超导态。将开展实验和理论研究，结合先进计算方法的预测能力，以更好地了解工作中的物理机制，并将有助于设计具有更高转变温度的超导材料的能力。该项目将提供对超导电子器件在低能电子、量子传感以及更重要的量子计算应用中应用的材料特性和现象的基本了解。将培养新一代科学家，他们深入参与实验和理论/模型研究，并补充专业知识。技术描述：二维(2D)范德华(VDW)材料的莫尔异质结构工程导致量子异质结构。利用最近展示的扭曲VDW异质外延，研究人员将构建VDW同/异结构，以实现出现在莫尔平带中的相关电子态。利用多尺度电子结构的理论和数学模型，该项目将对具有特殊性质的多层2D超导系统进行实验研究，如栅极可调转变温度和非传统配对对称性。将探索各种材料平台，包括扭曲的双双层石墨烯、扭曲的三层石墨烯和基于过渡金属二卤化物的扭曲的同质和杂化结构。理论指导将是本研究不可或缺的一部分，因为材料平台和扭转角度有多种选择，如果没有针对性的建模指导，仅靠实验是不能涵盖这些选择的。非常规超导性还可以导致拓扑超导体的发展和发现，这可以用于量子计算。由于基本量子态的拓扑性质，在拓扑超导系统中实现的量子比特为容错量子计算带来了希望。这一奖项反映了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: This project will investigate novel unconventional superconductors based on atomically thin materials stacked with a twisted angle between them. When two atomic layers with similar atomic structure meet each other, a larger scale quasi periodic structure called a moire pattern forms. Electronic structure of these interfacial structure can be engineered by adjusting the twisting angle. When the electron energy distribution is narrow, strong correlation between them appear, which can in turn drive the system to be a dissipationless superconducting state. Experimental and theoretical research, in conjunction with the predictive powers of advanced computational methods, will be developed to achieve a better understanding of the physical mechanisms at work and will contribute to the ability to design superconducting materials with higher transition temperatures. The project will provide fundamental understanding of the materials properties and phenomena that underpin superconducting electronic device applications in low energy electronics, quantum sensing, and more importantly quantum computing applications. A new generation of scientists will be trained who are deeply involved in both experimental and theoretical/modeling research with complimentary expertise.Technical Description: The moire heterostructure engineering of 2-dimensional (2D) van der Waals (vdW) materials leads to quantum heterostructures. Utilizing recently demonstrated twisted vdW heteroepitaxy, the investigators will construct vdW homo/hetero structures to realize correlated electronic states that appear in the moire flat bands. With inputs from theory and mathematical modeling of multiscale electronic structure, the project will experimentally investigate multilayer 2D superconducting systems with unusual properties, such as gate tunable transition temperature and non-conventional pairing symmetries. Various material platforms will be explored including twisted double bilayer graphene, twisted trilayer graphene and twisted homo- and hetetro-structures based on transition metal dichalcogenides. Theoretical guidance will be an indispensable part of this study since there are a variety of choices for material platforms and twist angle which cannot be covered by experiment alone without targeted modeling guide. Unconventional superconductivity can also lead into the development and discovery of topological superconductors, which can be utilized for quantum computing. The qubits realized in topological superconducting systems hold promise for fault-tolerant quantum computation, thanks to the topological nature of the underlying quantum states.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.