CAREER: Designing and Probing Emergent Phases with Tunable Magnons in Graphene

磁振子是磁性材料中的量子力学、波状物体，显示出与电子根本不同的特性。利用磁振子为创造自然界中找不到的合成物质和开发具有前所未有功能的下一代量子设备提供了一条有趣的途径。虽然电子的性质已经得到了深入的研究，但对磁振子及其在固体中的集体行为的研究仍然非常有限。探索这一方向的一个有前途的可调平台是石墨烯-一片碳原子-置于强磁场中，在那里可以有效地发射和检测磁振子。该项目的主要目标是探索可以通过使用磁振子作为构建模块来设计的可能的量子现象，并研究利用磁振子来探测原子薄材料的磁性的可行性。该项目的成功有望推进基础量子科学的前沿，并为未来的量子技术（如超低功耗信息设备）提供创新途径。该项目还通过为高中生、本科生和研究生提供的研究型教育和外展计划，将材料教育与日益增长的社会对量子技术的需求联系起来。技术摘要电荷中性玻色子的相关和拓扑状态的探索为推进我们对自然界中未发现的物质的涌现阶段的理解和解锁量子技术的新机遇提供了一条引人注目的途径。磁振子，也被称为自旋波，在单层石墨烯的量子霍尔铁磁态中，最近已经成为一个多功能的固态平台，用于设计和探测玻色子的涌现阶段，由于其非凡的可调性，长寿命，全电生成和检测方案以及对磁环境的显着敏感性。然而，我们对磁振子之间的相互作用及其与周围环境的耦合的了解仍然非常有限。该项目旨在通过实验解决这些关键问题，以促进未来磁振子和磁振子启用自旋探针的涌现阶段的理论分析和实验开发。这项研究是通过利用货车德瓦尔斯组装和摩尔量子物质的最新进展，沿着量子电子输运和扫描探针显微镜技术的创造性组合来提取超高质量石墨烯异质结构中磁振子的输运和热力学性质。最终，该项目为固体中玻色子的相关和拓扑相的设计、构造、表征和操纵提供了一条新的途径，并为解开二维材料中的相关现象建立了一种新的、通用的和有效的工具。此外，该项目还为本科生、研究生和高中教师提供了量子科学的研究和培训机会，并开设了二维量子材料的新课程，从而产生了更广泛的影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical abstractMagnons are quantum mechanical, wave-like objects in magnetic materials that display fundamentally different characteristics than electrons. Harnessing magnons presents an intriguing avenue for creating synthetic matter not found in nature and developing next-generation quantum devices with unprecedented functionalities. While the properties of electrons have been intensively studied, the investigation of magnons and their collective behavior in solids remains extremely limited. A promising and tunable platform to explore this direction is graphene - a sheet of carbon atoms - placed in a strong magnetic field, where magnons can be efficiently launched and detected. The primary goal of this project is to explore the possible quantum phenomena that can be engineered by using magnons as building blocks and to investigate the feasibility of utilizing magnons to probe the magnetic properties of atomically thin materials. The success of this project promises to advance the frontier of fundamental quantum science and enable innovative pathways to future quantum technologies such as ultra-low-power information devices. This project also connects materials education with the growing societal demand for quantum technology through research-informed education and outreach programs for high school, undergraduate, and graduate students.Technical AbstractThe exploration of correlated and topological states of charge-neutral bosons presents a compelling avenue for advancing our understanding of emergent phases of matter not found in nature and unlocking new opportunities in quantum technology. Magnons, also known as spin waves, in the quantum Hall ferromagnetic state of monolayer graphene, have recently emerged as a versatile solid-state platform for designing and probing emergent phases of bosons, owing to their extraordinary tunability, long lifetime, all-electrical generation and detection scheme and their remarkable sensitivity to the magnetic environment. However, our knowledge about the interaction between magnons and their coupling to the surrounding environments remains extremely limited. The project aims to experimentally address these key questions to facilitate future theoretical analysis and experimental development of emergent phases of magnons and a magnon-enabled spin probe. This investigation is made possible by leveraging recent advances in van der Waals assembly and moiré quantum matter, along with a creative combination of quantum electronic transport and scanning probe microscopy techniques to extract transport and thermodynamics properties of magnons in ultra-high-quality graphene heterostructures. Ultimately, this project provides a new pathway for the design, construction, characterization, and manipulation of correlated and topological phases of bosons in solids and establishes a new, generic, and effective tool for unraveling correlated phenomena in two-dimensional materials. In addition, this project has a broader impact through research and training opportunities in quantum science for undergraduates, graduate students, and high school teachers, and a new course on two-dimensional quantum materials.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.