MIRT: Building Functional Nanoarchitectures in van der Waals Materials

该材料跨学科研究小组（MIRT）的建议书研究了由不同货车德瓦耳斯（vdW）材料的“纳米层压”原子片创建的新型复合材料的组装和物理性能。 这些vdW构建块是其中原子键在两个方向上强，但在第三个方向上弱的材料。 这给了它们一个分层的结构，就像一叠纸，并且很容易分离（“剥落”）层。 常见的vdW材料包括石墨，它可以剥离形成单片（石墨烯）;许多高T超导体;和层状硫属化物，如MoS 2。 许多这些系统已经显示出有趣的行为，由于其电子结构的低维性。 该团队开创了一种以受控方式重新堆叠不同vdW材料的技术（“纳米层压”）。 使用这种技术，可以创建本质上是设计材料的异质结构，并在单个原子层的水平上进行控制。 MIRT的目标是创造出能够提供基础科学和工程应用所感兴趣的独特功能的材料。 MIRT的提案包括一个中心合成工作，旨在扩大正在研究的材料集，从第一个例子（石墨烯和六方氮化硼），包括层状硫属化物，二维氧化物，拓扑绝缘体和低维有机系统。 合成的努力结合纳米层压与单晶生长，分子束外延，模板材料生长和插层。 要解决的基本问题包括不同层之间的界面的性质，层间对齐如何改变属性，以及在VDW表面上生长的“设计规则”。 MIRT包括通过多种技术对新材料的广泛表征。 这些技术包括结构表征、电子输运、光学和拉曼光谱、扫描探针显微镜和化学方法。 利用MIRT计划开发的技术和材料，该团队试图解决一些关于低维材料行为的基本问题。 例如，当主体材料接近单原子片的极限时，将有可能研究相关电子行为的3D到2D演化，例如超导性和电荷密度波态。 同样，纳米层压技术将使拓扑绝缘体和超导体等材料相互接近，以探测预测存在于这些界面的奇异相。MIRT团队寻求通过REU和RET项目以及学校访问计划扩大其活动的影响。 此外，MIRT的一个中心目标是通过更好地协调研究和使用共享设施以及联合学生咨询和招生，加强哥伦比亚和CCNY之间的互动。

This Materials Interdisciplinary Research Team (MIRT) proposal examines the assembly and physical properties of new composite materials created by 'nano-laminating' atomic sheets of different van der Waals (vdW) materials. These vdW building blocks are materials in which the atomic bonds are strong in two directions, but weak in the third. This gives them a layered structure, like a stack of paper, and makes it easy to separate ('exfoliate') the layers. Common vdW materials include graphite, which can be exfoliated to form single sheets (graphene); many high-T superconductors; and layered chalcogenides such as MoS2. Many of these systems already display interesting behavior due to the low dimensionality of their electronic structure. The team pioneered a technique for re-stacking dissimilar vdW materials in a controlled fashion ('nano-lamination'). Using this technique, it is possible to create heterostructures that are essentially designer materials, with control at the level of the individual atomic layer. The aim of the MIRT is to create materials that provide unique functionality that is of interest to fundamental science and engineering applications. The MIRT proposal includes a central synthesis effort that seeks to broaden the set of materials under study from the first examples (graphene and hexagonal boron nitride) to include layered chalcogenides, 2D oxides, topological insulators, and low-dimensional organic systems. The synthesis effort combines nano-lamination with single-crystal growth, molecular beam epitaxy, templated materials growth, and intercalation. Fundamental issues to be addressed include the nature of interfaces between dissimilar layers, how interlayer alignment changes properties, and 'design rules' for growth on vdW surfaces. The MIRT includes extensive characterization of the new materials by multiple techniques. These techniques include structural characterization, electronic transport, optical and Raman spectroscopy, scanned probe microscopy, and chemical methods. Using the techniques and materials developed under the MIRT program, the team seeks to address a number of fundamental issues regarding behavior of materials in low dimensions. For instance, it will be possible to study the 3D-to-2D evolution of correlated electronic behavior such as superconductivity and charge density wave states as the host materials approach the limit of single atomic sheets. Likewise, nano-lamination will allow materials such as topological insulators and superconductors to be brought into proximity in order to probe exotic phases predicted to exist at these interfaces.The MIRT team seeks to broaden the impact of its activities through REU and RET programs, as well as a school visitation program. In addition, a central goal of the MIRT is to strengthen interaction between Columbia and CCNY through better coordination of research and use of shared facilities, as well as joint student advising and recruiting.