Understanding and Controlling Magnetic Two-Dimensional Crystals

磁性材料在通信、计算和先进电子学中有着广泛的应用。由于一种叫做自旋的量子特性，电子具有内在的磁性。块状材料中的磁性来自于这些自旋的耦合，这些自旋沿着相同的方向取向。该研究项目探讨了基于二维（2D）材料的新型永磁体的特性。对于这种原子级薄的材料，电子自旋的取向对局部环境和外部刺激非常敏感。这产生了传统磁体不可能实现的新的物理现象和设备功能。该项目将研究吸附分子，相邻层和机械应变对2D磁体性能的影响。我们的目标是学习如何控制它们的属性，从而可能导致创建按需物理属性和具有超紧凑外形和新颖功能的设备。高中，本科和研究生将接受2D材料制造和表征方面的丰富专业知识的培训。因此，该项目将有助于为美国未来的量子信息科学和技术做好准备。PI还将通过当地的教育活动提高公众对量子技术的认识。技术描述磁性2D材料为量子磁性的研究提供了一个理想的凝聚态平台，对二维磁体的控制可能为物质的新量子相和超磁电和磁光器件带来前所未有的机会。2D磁体的应用前景取决于磁性能的多样性，但仍然受到现状的阻碍：只有少数2D铁磁体被明确发现，其性能种类有限。通过设计实验来精细修改2D磁体的结构，电子和化学特性，该项目旨在揭示2D磁性对量子材料基本物理参数的复杂依赖性。基于这些基本的理解，可以开发重要的工程方法来创建“设计师”或“按需”磁量子材料特性。主要的研究方法包括控制2D磁体，使其受到实际影响因素的影响，如接触材料，吸附的化学物质和应变晶格，并通过一系列显微镜和光谱学（如扫描磁圆二色性和磁反射光谱）探测改变的性质。了解二维磁性与这些影响因素的关系，并由此开发工程方法，可以推动对二维磁体的前所未有的操纵，从而改变磁量子材料的格局，实现颠覆性的自旋电子和量子技术。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 DescriptionMagnetic materials have found widespread applications in communications, computing, and advanced electronics. Electrons possess have intrinsic magnetism, due to a quantum property called spin. Magnetism in a bulk materials arises from the coupling of these spins to be oriented along the same direction. This research project explores the properties of a new class of ultrathin magnets based on two-dimensional (2D) materials. For such atomically thin materials, the orientations of electron spins are very sensitive to the local environment and external stimulus. This gives rise to new physical phenomena and device functionality not possible from conventional magnets. This project will study the effects of adsorbed molecules, adjacent layers, and mechanical strain on the properties of 2D magnets. The goal is to learn how to control their properties, potentially leading to the creation of on-demand physical properties and devices with ultracompact form factors and novel functionality. High school, undergraduate, and graduate students will be trained with a rich set of expertise in 2D materials fabrication and characterization. This project will therefore help to prepare the future workforce for the quantum information science and technologies in the U.S. The PI will also raise the public literacy of quantum technologies through local educational activities.Technical DescriptionMagnetic 2D materials provide an ideal condensed matter platform for the study of quantum magnetism, and the control of 2D magnets potentially unlocks unprecedented opportunities for new quantum phases of matter and ultrathin magnetoelectric and magneto-optical devices. The breadth of application prospects of 2D magnets hinges on the diversity of magnetic properties but remains hindered by the status quo: only a small number of 2D ferromagnets have been unambiguously discovered, with a limited variety of properties. Through designing experiments to finely modify the structural, electronic, and chemical characteristics of 2D magnets, this project seeks to unravel the complex dependence of 2D magnetism on the basic physical parameters of quantum materials. Based on these fundamental understandings, vital engineering approaches can be developed to create “designer” or “on-demand” magnetic quantum materials properties. The main research approaches include controlling 2D magnets by subjecting them to practical influencing factors such as contacting materials, adsorbed chemicals, and strained lattices and probing the altered properties by a range of microscopies and spectroscopies such as scanning magnetic circular dichroism and the magneto-reflectance spectroscopy. Understanding 2D magnetism in relation to these influencing factors and developing engineering approaches therefrom could prompt unprecedented manipulation of 2D magnets, thereby transforming the magnetic quantum material landscape and enabling disruptive spintronic and 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.