Gate-Modulated Charge Density-Dependent Physics of Low-Dimensional Inorganic Semiconductors in Organic Multilayers

技术说明：拓扑绝缘体，例如硒化铋和碲化铋，是在其表面附近具有固有导电状态的材料。该研究项目利用多功能有机层来控制这些材料的表面化学势和键合相互作用，引入足够的电荷密度来揭示决定表面导电状态的原子和结构特征。分层结构用于封装拓扑绝缘体的薄膜，以在低施加电压下达到高电荷密度，最大化介电强度，并调节局部能带能量。局部电场被设计为与目前使用的离子液体中的电场一样大，但具有更好的限定几何形状。太赫兹磁光偏振仪将提供一个强大的探针，以确定散射率，电荷密度，并同时为几个平行的传输通道的带质量。该研究提供了观察物理现象的机会，如相关电子输运，拓扑绝缘体中的自旋极化传导，以及非常规超导性和电荷密度波。非技术描述：人们对能够以高能量效率操纵电和磁信号，并且能够越来越快地存储和处理信息的材料有很大的兴趣。该研究项目涉及研究一类新的类矿物材料，这些材料具有在某些位置非常有效地导电的特殊能力。开发了一种使用类塑料介质封装和切换这些材料的新方法。这种方法有望避免以前方法的一些复杂性，并允许更好地理解控制材料的电磁行为的因素。这项工作的结果将有助于为设计未来的计算机和数据管理系统创造新的可能性。本项目的研究生和本科生合成材料并进行材料和器件的表征，为多样化的科学和技术就业获得广泛的技术基础。这些活动也形成了本科材料科学和材料物理实验室课程的制造和表征模块的基础。来自西部高中的学生，一所公立的，主要是少数民族和低收入女子学校在巴尔的摩市，也参加了研究作为课后计划的一部分，并最终担任大使，以饲料中学以及。

Technical Description: Topological insulators, such as bismuth selenides and bismuth tellurides, are materials with inherent conductive states near their surfaces. This research project utilizes multifunctional organic layers to control the surface chemical potentials and bonding interactions in these materials, introducing sufficient charge density to reveal atomic and structural features that determine the surface conductive states. The layered structures are used to encapsulate thin films of topological insulators to reach a high charge density at low applied voltages, maximize dielectric strength, and tune local band energies. Local electric fields are designed to be as large as those in ionic liquids presently employed, but in a much better defined geometry. Terahertz magneto-optical polarimetry will provide a powerful probe to determine scattering rates, charge densities, and band masses for several parallel transport channels simultaneously. The research offers opportunities to observe physical phenomena such as correlated electron transport, spin polarized conduction in topological insulators, and unconventional superconductivity and charge-density waves. It can lead to new ways of controlling chalcogenide-organic interfaces in general.Non-technical Description: There is a great interest in materials that can manipulate electrical and magnetic signals with high energy efficiency, and that can store and process information more and more rapidly. This research project concerns the study of a new class of mineral-like materials that have a special ability to conduct electricity very effectively at certain locations. A new way to package and switch these materials using plastic-like media is developed. This method is expected to avoid some of the complications of previous methods and allow better understanding of the factors that control the electrical and magnetic behavior of the materials. The result of this work will help to create new possibilities for designing future computers and data management systems. Graduate and undergraduate students in this project synthesize materials and perform characterizations of materials and devices, acquiring a broad technical basis for diversified science and technology employment. These activities also form the basis of fabrication and characterization modules in undergraduate materials science and materials physics laboratory courses. Students from Western High School, a public, largely minority and low-income girl's school in Baltimore City, also participate in the research as part of an after-school program, and ultimately serve as ambassadors to feeder middle schools as well.