RUI: Magnetic Phase Transitions in Intercalated Dichalcogenides

* 技术摘要 * 过渡金属二硫属化物如二硫化钛具有由沿c轴沿着堆叠的原子三层组成的层状晶体结构。三层膜受货车范德华力的弱束缚。 纯的二硫属化合物表现出有趣的性质，如电荷密度波和超导性。外来原子可以被引入到层间间隙中，这被称为嵌入。本计画将探讨磁性离子插层对二硫属化合物材料性质的影响。通过改变插入剂的类型和含量以及主体的性质，将控制磁性相之间的竞争并研究相之间的转变。准一维纳米结构也将被制造和研究。该项目的成果是更好地了解结构和相互作用如何决定二硫属化物和其他材料（如锰氧化物）的磁性基态。本科生将深入参与样品制造，测量和数据分析。本科研究的功效，培养学生在科学推理和写作将使用国家认可的工具进行评估。来自代表性不足群体的高中生也将沉浸在研究环境中并接受指导。非技术摘要 * 过渡金属二硫属元素（例如二硫化钛）具有由原子层（三个原子厚）沿垂直于层的方向沿着堆叠组成的晶体结构。这些层之间的结合很弱，这使得在一个称为插层的过程中可以在层之间引入新的原子。插层材料具有反映主体和插入原子的性质的性质。因此，人们可以通过控制嵌入原子的类型和数量来控制材料的整体性质。这种可调材料在新的磁性和电子器件中可能非常有用，其中可以通过控制嵌入剂的性质来设计特定的特性。这个项目将研究各种插层的二硫属化物，包括新制造的纳米管。将仔细测量磁性和电子特性，以全面了解这些材料的行为。然后将评估其应用潜力。本科生将在研究的各个方面发挥不可或缺的作用。本科生的科研训练学生在科学推理和写作的功效将进行评估。来自代表性不足群体的高中生也将沉浸在研究环境中并接受指导。

****Technical Abstract****Transition-metal dichalcogenides such as titanium disulfide possess a layered crystal structure consisting of atomic trilayers stacked along the c axis. The trilayers are weakly bound by van der Waals forces. Pure dichalcogenides exhibit interesting properties such as charge density waves and superconductivity. Foreign atoms can be introduced into the interlayer gaps; this is called intercalation. In this project, the effects of intercalating magnetic ions on the properties of dichalcogenide materials will be experimentally investigated. By varying the type and content of the intercalant and the nature of the host, competition between magnetic phases will be controlled and transitions between phases studied. Quasi-one-dimensional nanostructures will also be fabricated and studied. The outcome of the project is a better understanding of how structure and interactions determine magnetic ground states in the dichalcogenides and other materials such as manganites. Undergraduates will be deeply involved in sample fabrication, measurements and data analysis. The efficacy of undergraduate research for training students in scientific reasoning and writing will be assessed using nationally recognized instruments. High-school students from underrepresented groups will also be immersed and mentored in the research environment.****Non-Technical Abstract****Transition-metal dichalcogenides (for example, titanium disulfide) have a crystal structure consisting of layers of atoms (three atoms thick) stacked along a direction perpendicular to the layers. The layers are weakly bonded, which permits the introduction of new atoms between the layers in a process called intercalation. The intercalated material has properties that reflect both those of the host and the inserted atoms. Thus, one can control the overall properties of the material by controlling the type and number of intercalant atoms. Such tunable materials could be very useful in new magnetic and electronic devices in which specific characteristics could be engineered by controlling the properties of the intercalant. This project will investigate a variety of intercalated dichalcogenides, including newly fabricated nanotubes. Magnetic and electronic properties will be carefully measured to obtain a thorough understanding of the behavior of these materials. Their potential for applications will then be evaluated. Undergraduate students will play an integral part in every aspect of the research. The efficacy of undergraduate research for training students in scientific reasoning and writing will be assessed. High-school students from underrepresented groups will also be immersed and mentored in the research environment.