Collaborative Research:Theory-guided Design and Discovery of Rare-Earth Element 2D Transition Metal Carbides MXenes (RE-MXenes)

在降低能耗和碳足迹的同时，对更高计算能力和数据存储的需求不断增长，这需要新的材料和计算范式。经过几十年的积极小型化，电子设备目前正走到传统材料的尽头，因为我们“耗尽了原子”，这一事实加剧了这种需求。二维（2D）材料是一种相对较新的材料，由几个原子厚的薄片组成，为解决这些挑战提供了一个平台。特别有趣的是被称为MXenes的二维过渡金属碳化物，它由两到四个由碳原子层隔开的过渡金属原子层组成。研究了MXenes的各种应用，包括储能和发电、阻挡电磁波和天线。尽管取得了重大进展，但对量子计算、计算机存储器和自旋电子学很重要的室温磁性仍然难以捉摸。在材料研究部固态和材料化学项目的支持下，印第安纳大学的Babak Anasori教授和普渡大学的Alejandro Strachan教授及其研究小组将设计和制造含有稀土元素（如钕和钆）的新型2D MXenes，并对如何使用这些元素来控制电子、磁性、以及这些材料的光学性质。计算建模用于指导这些新材料的实验设计，并将实验次数减少到最有希望的候选材料。该团队假设在MXenes中使用稀土元素可以产生第一个室温二维磁体。为了加速创新，所有产生的实验和理论结果以及开发的模型都将对研究人员和教育工作者开放，用于在线计算。纳米材料和二维材料的显微图像已被用于许多纳米艺术可视化，如纳米艺术摄影，以促进STEM。纳米艺术图像将被整合到当地的纳米科学推广活动中，比如普渡大学的纳米日，以激励对艺术充满热情的孩子们有机会了解纳米艺术图像背后的科学和工程。在过去的十年中，二维过渡金属碳化物MXenes已经成为最大的二维材料家族之一。MXenes具有金属导电性，亲水性，能够插入大量离子和有机分子，在储能，电磁干扰（EMI）屏蔽，无线通信，催化和生物医学等应用中具有出色的性能。双过渡金属MXenes是MXenes的一个亚族，可以通过改变MXenes过渡金属成分来实现显著的性能可调性。这项研究得到了材料研究部固态和材料化学项目的支持，旨在设计、合成和表征一种新的二维双过渡金属碳化物家族：稀土（RE） f元素二维MXenes，开辟了磁性质的可能性。这将通过理论和实验的协同结合来实现。该项目的总体目标是发展对不同稀土元素如何被纳入MXenes的基本理解，并利用它来控制这些新相的电子、光学和磁性能。阻碍f元素MXenes的限制因素是它们的合成，需要在大的组成空间中设计新颖的f元素MAX相前驱体。该项目使用高通量第一性原理和热力学计算来识别稳定的前体及其MXenes，并使用数据科学工具指导实验工作。稀土f元素MXenes可以具有完全不同的性质，这些性质在常规的MXenes中从未被测量过，在其他二维和块状材料中也不存在。稀土MXenes具有从电磁干扰屏蔽、光电子学、催化到量子计算、自旋电子学和磁电子学的潜在应用。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 SUMMARYThe ever-increasing demand for higher computing power and data storage while reducing power consumption and carbon footprint calls for new materials and computing paradigms. This need is accentuated by the fact that after decades of aggressive miniaturization, electronic devices are currently reaching the end of the road for traditional materials as we “run out of atoms”. Two-dimensional (2D) materials, a relatively new class of materials consisting of few-atom-thick sheets, provide a platform to address these challenges. Particularly interesting are 2D transition metal carbides, known as MXenes, composed of two to four atomic layers of transition metals separated by an atomic layer of carbon. MXenes are studied for various applications, including energy storage and generation, blocking electromagnetic waves, and antenna. Despite significant progress, room temperature magnetism, important for quantum computation, computer memories, and spintronics, has remained elusive. With this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, Professor Babak Anasori at Indiana University Purdue University Indianapolis and Professor Alejandro Strachan at Purdue University and their research groups will design and fabricate novel 2D MXenes that contain rare-earth elements, such as neodymium and gadolinium, and develop a fundamental understanding of how such elements can be used to control the electronic, magnetic, and optical properties of these materials. Computational modeling is used to guide the experimental design of these new materials and reduce the number of experiments to the most promising candidates. The team hypothesizes that the use of rare-earth elements in MXenes can lead to the first room-temperature 2D magnets. To accelerate innovation, all experimental and theoretical results produced and models developed will be made accessible for the researchers and educators for online computing. The microscopic images of nanomaterials and 2D materials have been used in many nanoart visualizations, such as NanoArtography, to promote STEM. The nanoart images will be integrated into local nanoscience outreach activities, such as Purdue’s NanoDays, to motivate art-enthusiastic children to have a chance to learn about the science and engineering behind nanoart images.TECHNICAL SUMMARY2D transition metal carbide MXenes have become one of the largest 2D material families over the past decade. MXenes have metallic electrical conductivities, are hydrophilic, and capable of intercalating a host of ions and organic molecules, leading to outstanding performance in applications such as energy storage, electromagnetic interference (EMI) shielding, wireless communications, catalysis, and biomedicine. Double-transition metal MXenes are a subfamily of MXenes that enable significant tunability in properties by changing the MXenes transition metal compositions. The research, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, aims to design, synthesize, and characterize a new family of 2D double-transition metal carbides: rare-earth (RE) f-element 2D MXenes opening the possibility of magnetic properties. This will be accomplished via a synergistic combination of theory and experiments. The overarching goal of this project is to develop a fundamental understanding of how different rare-earth elements can be incorporated into MXenes and use it to control the electronic, optical, and magnetic properties of these novel phases. The limiting factor hindering f-element MXenes is their synthesis that requires the design of novel f-element MAX phase precursors among the large compositional space. This project uses high-throughput first principles and thermodynamic calculations to identify stable precursors and their MXenes and use data science tools to guide experimental efforts. Rare-earth f-element MXenes can have radically different properties that have never been measured in regular MXenes and are absent in other 2D and bulk materials. Rare-earth MXenes can have potential applications from EMI shielding, optoelectronics, and catalysis to quantum computation, spintronics, and magnetoelectronics.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.