Center for Functional Nanomaterials , Brookhaven National Lab , Upton , New York 11973 , United States.
Nano Lett. 2019 Feb 13;19(2):716-721. doi: 10.1021/acs.nanolett.8b03751. Epub 2019 Jan 28.
The search for new topological materials and states of matter is presently at the forefront of quantum materials research. One powerful approach to novel topological phases beyond the thermodynamic space is to combine different topological/functional materials into a single materials platform in the form of superlattices. However, despite some previous efforts there has been a significant gap between theories and experiments in this direction. Here, we provide the first detailed set of experimentally verifiable phase diagrams of topological superlattices composed of archetypal topological insulator, BiSe, and normal insulator, InSe, by combining molecular-level materials control, low-temperature magnetotransport measurements, and field theoretical calculations. We show how the electronic properties of topological superlattices evolve with unit-layer thicknesses and utilize the weak antilocalization effect as a tool to gain quantitative insights into the evolution of conducting channels within each set of heterostructures. This orchestrated study opens the door to the possibility of creating a variety of artificial-topological-phases by combining topological materials with various other functional building blocks such as superconductors and magnetic materials.
目前，寻找新的拓扑材料和物质状态是量子材料研究的前沿领域。超越热力学空间的新型拓扑相的一种强大方法是将不同的拓扑/功能材料组合成超晶格形式的单个材料平台。然而，尽管之前有一些努力，但在这一方向上，理论和实验之间存在着显著的差距。在这里，我们通过结合分子级材料控制、低温磁输运测量和场理论计算，提供了由典型拓扑绝缘体 BiSe 和正常绝缘体 InSe 组成的拓扑超晶格的第一个详细的实验可验证的相图集。我们展示了拓扑超晶格的电子性质如何随单层厚度而演化，并利用弱反局域效应作为工具，对各异质结构中导带的演化获得定量的认识。这项精心设计的研究为通过将拓扑材料与各种其他功能构建块（如超导体和磁性材料）相结合来创造各种人工拓扑相开辟了可能性。
