Exploration of Dynamically Reconfigurable Topological Insulators for Enabling Next-Generation Acoustic-Based Logic and Signal Processing

本项目将产生关于动态可重构拓扑绝缘体的新知识，为科学进步和国家健康、安全和繁荣作出贡献。拓扑绝缘体是一种具有独特特性的材料，允许信号通过其边缘，而不是表面。该项目的成果将有助于可重构拓扑绝缘体技术的发展。这些技术在通信设备、传感器和机器人技术中有许多应用，包括蜂窝电话、触摸屏和微流体设备。教育推广计划通过乔治亚州教师实习奖学金（GIFT）项目向代表性不足的高中学生和他们的教师进行推广，而招收新的研究生将包括向亚特兰大当地的几所传统黑人学院和大学（HBCUs）进行推广。这项研究的结果，连同教育外展，将告知科学界和一大批不同的学生关于波和机电系统物理学的新发现，这有望激励下一代的科学家和工程师。拓扑绝缘体代表了一类新的材料，其中块状材料表现为绝缘体（即阻止波传播），而外围允许这种传播（例如，边缘传播或界面传播）。此外，由于拓扑保护，这些边缘模式不受后向散射的影响，因此本质上不受缺陷和不完美的影响。这项研究将通过使用理论、计算和实验技术，展示第一个可重构的机械拓扑绝缘体。要探索的概念包括使用螺线管和压电驱动的可重构性的机械手段。这两种方法都会破坏反转对称性，导致材料的狄拉克结构分离，产生非平凡陈氏数（拓扑的整数度量）和拓扑绝缘体。预计这将为新型商业上可行的波导、滤波器和逻辑器件开辟道路，这些器件不受缺陷和异常的后向散射的影响。就像无处不在的表面声波（SAW）设备一样，这些新设备预计在尺寸和成本方面比电磁设备具有优势，并且预计比数字信号处理等软件解决方案更高效（例如，消耗更少的电池电量）。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will contribute to the progress of science and advance the national health, security and prosperity, by producing new knowledge on dynamically reconfigurable topological insulators. The topological insulators are materials with unique properties that allow signals to travel through their edges, but not the surface. Outcomes of this project will contribute to the advancement of reconfigurable topological insulators technologies. These technologies have a number of applications in communication devices, sensors and robotics, including cellular phones, touch screens, and microfluidic devices. Educational outreach is planned to underrepresented high school students and their teachers through the Georgia Intern Fellowships for Teachers (GIFT) program, while recruitment of new graduate students will include reaching out to several Historically Black Colleges and Universities (HBCUs) local to Atlanta. Findings from the research, together with educational outreach, will inform the scientific community and a large and diverse cohort of students about new discoveries in the physics of waves and electromechanical systems, which is expected to inspire the next generation of scientists and engineers.Topological insulators represent a new class of materials in which the bulk material behaves as an insulator (i.e., prevents wave propagation), while the periphery allows such propagation (e.g., edge propagation or interface propagation). Furthermore, due to topological protection, these edge modes are protected from backscattering, and are therefore intrinsically protected from the presence of defects and imperfections. This research will demonstrate the first reconfigurable, mechanical topological insulators through the use of theoretical, computational, and experimental techniques. Concepts to be explored include mechanical means of reconfigurability using solenoids and piezoelectric actuation. Both means will break inversion symmetry, resulting in a separation of the material's Dirac structure, yielding non-trivial Chern numbers (an integer measure of topology) and thus topological insulators. This is anticipated to open pathways to new classes of commercially viable waveguides, filters, and logic devices immune to back-scattering from defects and anomalies. Much like ubiquitous surface acoustic wave (SAW) devices, these new devices are expected to have advantages over their electromagnetic counterparts in terms of size and cost, and are expected to be more efficient (e.g., consume less battery power) than software solutions such as digital signal processing.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.