Collaborative Research: RUI: Patterned Doping of Layered Materials

摘要：研究小组已经开发出一种在微米和纳米尺度上将杂质掺入层状材料（如石墨）的方法。这些杂质改变了层状材料的物理、电子和光学性质。这些特性在太阳能电池、发光二极管（led）和量子计算机等领域都有应用。在纳米尺度上控制杂质的能力使科学家和工程师能够减小当前设备的尺寸，甚至可能发现新的应用。本研究的目的是使用多学科的方法来获得这些样本的更完整的理解。北爱荷华大学领导了杂质样品的制造工作以及其物理和电子特性的表征。光学特性将在德克萨斯理工大学进行表征。这项研究涉及到接受各种技术和技术训练的本科生。这样的环境造就了全面发展的学生，为工业界或学术界的职业生涯做好了准备。作为K-12教育的领导者，北爱荷华大学为该项目提供了一个极好的机会，可以对来自不同背景的小学，初中和高中学生产生积极的影响。与高中科学教师的定期接触，可以直接展示教师的研究活动和学生的机会。这些努力鼓励学生探索STEM（科学、技术、工程和数学）领域的职业。技术摘要：层状晶体具有丰富多样的相，如磁性、自旋玻璃行为、超导性和电荷密度波。这些相可以在纯体系中自然发生，也可以通过掺杂诱导、破坏或修饰。插层是掺杂的一种形式，在分子层之间插入原子或分子。研究小组发现了一种利用聚焦高能电子束局部插入层状晶体的新方法。本研究的目的是探索在微米和纳米尺度上控制层状晶体相的能力。创造局部相变的能力允许探索不同电子或磁相之间的一系列边界条件，以及它们之间的隧道。该技术可用于有限层系统，以减少层间耦合，并可能为全新的二维行为创造新的机会。北爱荷华大学和德克萨斯理工大学之间的合作努力结合了原子力显微镜、扫描隧道显微镜和拉曼光谱的能力，以表征这些材料的局部物理、电学和光学特性。pi与各种各样的研究助理一起工作，并吸引来自各种背景和专业的本科生。这项合作工作的另一个好处是，来自爱荷华州的本科生有机会与来自德克萨斯理工大学的研究生一起工作。德克萨斯州的拉伯克与印第安纳州的锡达福尔斯有着非常不同的文化和人口，这将有利于所有学生学习与来自不同背景的人一起工作，这是现代研究所必需的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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 Abstract: The research team has developed a method to incorporate impurities into layered materials, such as graphite, on the micrometer and nanometer scale. These impurities modify the physical, electronic, and optical properties of the layered materials. These properties have applications in solar cells, light emitting diodes (LEDs), and quantum computers to name a few. The ability to control impurities at the nanometer scale enables scientists and engineers to reduce the size of current devices, and possibly even discover new applications. The goal of this research is to use a multidisciplinary approach to obtain a more complete understanding of these samples. The University of Northern Iowa leads the fabrication efforts of impurity samples as well as characterization of their physical and electronic properties. Optical properties will be characterized at Texas Tech University. This research involves undergraduate students trained on a wide variety of techniques and technologies. Such an environment results in well-rounded students ready for careers in either industry or academia. As a leader in K-12 education, the University of Northern Iowa provides an excellent opportunity for this project to have a positive impact on elementary, middle, and high school students from diverse backgrounds. Regular contact with high school science teachers allows faculty research activities and student opportunities to be showcased directly. Such efforts encourage students to explore careers in STEM (science, technology, engineering, and mathematics) fields. Technical Abstract: Layered crystals exhibit a rich variety of phases such as magnetism, spin-glass behavior, superconductivity, and charge density waves. These phases can occur naturally in pure systems or be induced, disrupted, or modified via doping. Intercalation is a form of doping, in which atoms or molecules are inserted between the molecular layers. The research team has discovered a new method to locally intercalate layered crystals using a focused high energy electron beam. The goal of this research is to explore the ability to control phases in layered crystals on the micrometer and nanometer scale. The ability to create localized phase changes permits an exploration of a range of boundary conditions between different electronic or magnetic phases, as well as tunneling between them. This technique can be used in finite layer systems to reduce interlayer coupling and perhaps create new opportunities for entirely new two-dimensional behaviors.The collaborative effort between the University of Northern Iowa and Texas Tech University has the combined capabilities of atomic force microscopy, scanning tunneling microscopy, and Raman spectroscopy to characterize the local physical, electrical, and optical properties of these materials. The PIs work with a diverse group of research assistants and attract undergraduates from a variety of backgrounds and majors. An additional benefit of this collaborative work is the opportunity for undergraduate students from Iowa to work with graduate students from Texas Tech University. Lubbock, TX, has a very different culture and population than Cedar Falls, IA, which will benefit all students in learning to work with individuals from diverse backgrounds as is necessary in modern research.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.