Understanding and Controlling Magnetic Two-Dimensional Crystals

非技术描述磁性材料在通信、计算和先进电子设备中得到了广泛的应用。由于一种称为自旋的量子性质，电子具有本征磁性。块状材料中的磁性来自于这些自旋沿同一方向定向的耦合。本研究项目探索了一种基于二维材料的新型超薄磁体的性能。对于这种原子薄的材料，电子自旋的取向对局域环境和外部刺激非常敏感。这带来了新的物理现象和设备功能，这是传统磁体无法实现的。本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。目标是学习如何控制它们的属性，潜在地导致创建具有超紧凑外形和新颖功能的按需物理属性和设备。高中生、本科生和研究生将接受2D材料制造和表征方面的丰富专业知识培训。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。该协会还将通过当地的教育活动提高量子技术的公众素养。技术说明磁性2D材料为量子磁学的研究提供了理想的凝聚态平台，而对2D磁体的控制可能为物质和超薄磁电和磁光器件的新量子相打开前所未有的机会。2D磁体应用前景的广度取决于磁性的多样性，但仍然受到现状的阻碍：只有少量的2D铁磁体被明确发现，性能的多样性有限。通过设计实验来精细地改变2D磁体的结构、电子和化学特性，该项目试图揭示2D磁体对量子材料基本物理参数的复杂依赖关系。在这些基本认识的基础上，可以开发出重要的工程方法来创造“设计者”或“按需”磁量子材料的性质。主要的研究方法包括通过使2D磁体受到接触材料、吸附的化学物质和应变晶格等实际影响因素的控制，以及通过扫描磁二色谱和磁反射光谱等一系列显微镜和光谱来探测改变的性能。了解与这些影响因素相关的2D磁性并由此开发工程方法可能会促使对2D磁体进行前所未有的操作，从而改变磁性量子材料的格局，并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 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.