Non-centrosymmetric Quantum Materials through Metal-amine Complexes

在材料研究部固态和材料化学计划的支持下，首席研究员(PI)Efrain Rodriguez教授和他在马里兰大学的研究小组将开发由铁、钴和镍等元素组成的新型量子材料，这些元素夹在硫等其他元素的薄层之间。开发具有独特量子性质的新型电子材料的概念，可以使许多科学家长期追求的量子信息革命成为可能。这项工作的一个独特方面是，金属硫化物层的结合调用了其他物理性质，如磁性，这些性质对量子信息应用很有吸引力。然而，这些层并不是随机堆积在另一层之上，而是插入引导堆积顺序的分子。因此，原子水平的化学控制允许这些分子将金属硫化物层“扭曲”或“弯曲”，以产生对量子技术有吸引力的特性。这种在原子尺度上的精确控制使新型量子材料的设计成为可能。这些研究活动还包括通过使用3D打印机向大学园区周围的当地社区宣传教育。PI和他的学生从化学数据库中提取了近50种不同的分子和材料，并将它们转化为3D打印结构。他们的模型工具包名为MolecularCraft，在当地高中的化学课堂上充当教学工具。PI与附近兰利公园国际高中(IHSLP)的教职员工合作，这是一所为STEM中代表性不足的学生提供服务的学校。PI和马里兰大学的学生建议与IHSLP的学生接触，不仅使用当地的3D打印机，而且还使用大学校园的资源。其目的是向学生传授使技术成为可能的材料，并激励他们考虑从事STEM职业。技术概述这个项目由材料研究部的固态和材料化学计划支持，将研究如何形成两个或更多不同的成分，以创造新型杂化材料，从而为新出现的现象开辟新的途径。在拟议的研究活动中，杂化材料包括插入到二维金属硫化物中的金属-胺络合物。金属-胺分子单元是手性的，作为结构导向剂形成打破反转对称性的晶体结构。研究还考察了金属胺络合物的-NH_2基团与金属硫化物末端的Q2-阴离子(Q=S和Se)之间的氢键大小对晶体结构的影响。为了产生非中心对称的量子材料，这种相互作用应该扭曲或弯曲2D层。非中心对称量子材料晶体生长是在溶剂热条件下进行的。晶体生长的溶剂是胺双酯配体L，它形成[ML3]n络合物，其中M=Mn、Fe、Co、Ni或Cu。寄主MQ层被归类为四面体过渡金属硫化物(TTMCs)，与研究较多的过渡金属二盐基化物(如MoS_2，WTe_2)不同，它具有正方形的金属亚晶格，并容纳第一排较小的过渡金属。目标相包括用于非中心对称超导电性的铁基和镍基TTMCs以及用于铁电巡游磁性的Co和Mn基TTMCs。与当地学校IHSLP的接触，使用3D打印来教授学生关于无机分子和无机材料的知识。学生学习结构与性质的关系，以及在充电电池、太阳能电池和超导体等技术中发挥重要作用的材料。3D打印分子工艺工具包从价壳电子对排斥(VSEPR)理论开始，向学生传授结构基础知识。IHSLP还具有3D打印功能，PI有一个网页，当前托管所有3D打印文件。代表性也很重要，因此另一个目标包括向学生展示科学领域更多样化的代表性。3D打印项目作为一座桥梁，将他们与通往不同STEM职业道路的信息联系起来。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 summaryWith this project, supported by the Solid State and Materials Chemistry Program in the Division of Materials Research, principal investigator (PI) Prof. Efrain Rodriguez and his research group at the University of Maryland will develop new types of quantum materials consisting of elements such as iron, cobalt, and nickel that are sandwiched between thin layers of other elements such as sulfur. The concept of developing new types of electronic materials that possess unique quantum properties can enable the revolution in quantum information long sought after by many scientists. A unique aspect of the work is that the incorporation of metal sulfide layers invokes other physical properties such as magnetism that are enticing for quantum information applications. These layers, however, do not randomly stack on top of one another and instead molecules are inserted that guide the stacking sequence. Chemical control at the atomic level therefore allows these molecules to ‘twist’ or ‘bend’ the metal sulfide layers into producing attractive properties for quantum technologies. This precise control at the atomic scale allows the design of novel quantum materials. These research activities also include outreach to the local community around College Park in education through the use of 3D printers. The PI and his students have taken close to 50 different molecules and materials from chemical databases and turned them into 3D printed structures. Their model kits called MolecularCraft serve as instructional tools in the chemistry classroom in local high schools. The PI collaborates with the faculty at the nearby International High School at Langley Park (IHSLP), which is a school that serves students underrepresented in STEM. The PI and students from the University of Maryland propose to engage with IHSLP students using their local 3D printers but also resources on the university campus. The aim is to teach the students about materials that make technologies possible and to inspire them to consider STEM careers.Technical summaryThis project, supported by the Solid State and Materials Chemistry Program in the Division of Materials Research, will examine how two or more disparate components can be formed to create new types of hybrid materials which can open new avenues towards emergent phenomena. In the proposed research activities, hybrid materials consist of metal-amine complexes inserted into two-dimensional (2D) metal chalcogenides. The metal-amine molecular units are chiral and serve as structure directing agents to form crystal structures that break inversion symmetry. The research activities also investigate how much hydrogen bonding between the –NH2 groups of the metal amine complexes and the terminal Q2- anions (Q = S and Se) of the metal chalcogenides dictates crystal structure. To give rise to non-centrosymmetric quantum materials, such interactions should either twist or bend the 2D layers. The crystal growth of non-centrosymmetric quantum materials takes place under solvothermal conditions. The solvent for crystal growth is an amine bidendate ligand L that forms [ML3]n+ complexes, where M = Mn, Fe, Co, Ni, or Cu. The hosting MQ layers are classified as tetrahedral transition metal chalcogenides (TTMCs), which in contrast to the well-studied transition metal dichalcogenides (e.g. MoS2, WTe2), have a square metal sublattice and accommodate smaller transition metals of the first row. The targeted phases include Fe- and Ni-based TTMCs for non-centrosymmetric superconductivity and Co- and Mn-based TTMCs for ‘ferroelectric’ itinerant magnetism. Outreach to the local school, IHSLP, uses 3D printing to teach students about inorganic molecules and inorganic materials. Students learn about structure-property relationships and about materials that play important roles in technology such as rechargeable batteries, solar cells, and superconductors. The 3D printing MolecularCraft kits start with Valence Shell Electron Pair Repulsion (VSEPR) theory, to teach students the basics of structure. IHSLP also has 3D printing capabilities, and the PI has a webpage where all the 3D printing files are currently hosted. Representation matters too, so another goal includes demonstrating to the students a more diverse representation in the sciences. The 3D printing project serves as a bridge to connect them with information on the pathways to different STEM careers.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.