Development of Chiral Charge Density Wave Electronic Devices

这一提议的目的是对手性电荷密度波系统的性质有一个基本的了解，并利用集体电荷系统的手征态的独特优势来创造新的电子器件。理解手性电荷密度波的本质，学习如何操纵手性电荷域，将对凝聚态物理产生变革，并将为基于集体电子激发的器件打开大门。在电子设备中使用集体充电系统的主要优势是在高器件密度下功耗较低。基础研究将包括对精心设计的二维材料中手性电荷密度波态的宏观和原子尺度的研究。该计划将为学生和青年研究人员提供必要的工具，以在材料科学、凝聚态物理和电子设备工程领域开展现代基础研究。由于设计的研究活动是高度跨学科的，学生将被鼓励参加跨学科的课程，如纳米科学、电子和扫描探针显微镜以及纳米制造。该计划旨在通过以下方式扩大学生的参与度和鉴赏力：(A)在现有的本科生和研究生水平的纳米科学、纳米电子学和固态物理课程中融入研究元素；(B)培训学生使用最先进的制造和表征工具；(C)让学生接触到不同组织的研究企业和协作研究。这项工作将导致培养一名博士生和几名本科生。通过高级论文工作经验和科学研究俱乐部以及学院的开放参观来接触当地高中是为高中生攻读理工科学位做准备的过度战略的一部分。手性打破了空间反转对称性，导致了意想不到的新电子特性，特别是在降维的系统中。在许多情况下，电子手性是由其产生的系统的特定结构促成的，无论是原子尺度上还是介观尺度上。最近，人们发现宏观关联电子态之一的电荷密度波也表现出手性性质。这一方案探索了利用具有相反手性的纳米尺寸的磁畴作为存储和逻辑单元的基本元件的机会，该研究的目的是从根本上了解手性电荷密度波与外部扰动(如光、准静态电场和磁场)耦合的本质，目的是主动地控制和测量单个电荷密度波域的手征状态。成功地操纵和读出单个纳米尺寸结构域的手性态将使手性电荷系统在信息存储和处理中得到应用。为了实现这一目标，研究人员将合成手性电荷密度波材料的单晶，对二盐基化物的单晶和剥离的几层晶体进行局部扫描探针表征和整体表征。在几层单晶上的扫描隧道显微镜以及将光耦合到扫描隧道显微镜结将在识别手性结构域操纵的实际区域方面发挥重要作用。在电子器件中使用集体手性态可以极大地扩展互补金属氧化物半导体的电流向下限制，该限制是由非相干电子器件中的功率耗散水平设置的。基础研究将包括宏观和原子尺度上对精心设计的二维材料中手性电荷密度波态的研究，从而清楚地揭示耦合激子和电荷密度波关联的复杂介观物理。

The goal of this proposal is to gain a fundamental understanding of the properties of chiral charge density wave systems and create new electronic devices exploiting unique advantages of the chiral state of the collective charge system. Understanding the nature of chiral charge density wave and learning how to manipulate chiral charge domains will be transformative to the condensed matter physics and it will open the doors to devices based on collective electron excitations. The main advantage of using collective charge systems for electronics is lower power dissipation at high device densities. The fundamental studies will involve both macroscopic and atomic scale investigations of the chiral charge density wave states in carefully engineered two-dimensional materials.The program will provide students and young researchers with necessary tools to carry out modern fundamental research in the fields of materials science, condensed matter physics and electronic device engineering. Since the designed research activities are highly interdisciplinary, the students will be stimulated to take classes across disciplines, such as nanoscience, electron and scanning probe microscopy and nanofabrication. The plan is to broaden participation and appreciation of students through (a) incorporating elements of the research in existing nanoscience, nano-electronics and solid-state physics courses at both the undergraduate and graduate level; (b) train students to use state of the art fabrication and characterization tools and (c) expose the students to research enterprise and collaborative research across different organizations. This work should lead to training a PhD student and several undergraduate students. Outreach to local area high schools through senior thesis work experience and science research clubs as well as College's open houses are part of the overreaching strategy to prepare high school students to pursue science and engineering degrees.Chirality breaks down the spatial inversion symmetry and results in unexpected new electronic properties, in particular in systems with reduced dimensionality. In many cases the electronic chirality is facilitated by the specific structure of the system in which it emerges, either on atomic scale or on mesoscopic scale. Recently, it was discovered that one of the well-studied macroscopically correlated electronic state, the charge density wave, also exhibits chiral properties. This proposal explores the opportunity to use the nanometer-size domains of opposite chirality that are separated with domain walls as basic elements for memory and logic units.The goal of the research is to gain a fundamental understanding of the nature of the coupling of the chiral charge density waves with external perturbations, such as light, quasi static electric and magnetic fields with the aim of actively controlling and measuring the chiral state of individual charge density wave domains. Successful manipulation and read-out of the chiral state of individual several nanometer-size domains would enable utilization of the chiral charge systems in information storage and processing. To achieve this goal the investigators will synthesize single crystals of chiral charge density wave materials, conduct local scanning probe characterization as well as bulk characterization on both single crystal and exfoliated few layer crystals of dichalcogenides. Scanning tunneling microscopy on few-layer single crystals as well as coupling the light to the scanning tunneling microscopy junction will play important role in identifying practical regimes for chiral domain manipulation. The use of collective chiral states in electronic devices could dramatically extend the current down-scaling limit of complementary metal-oxide semiconductors that is set by the level of power dissipation in incoherent electron based devices. The fundamental studies will involve both macroscopic and atomic scale investigations of the chiral charge density wave states in carefully engineered two-dimensional materials, thus clearly exposing the complex mesoscopic physics that couples excitonic and charge density wave correlations