Topological Straintronic Devices

非技术：在过去的半个世纪里，半导体技术推动了信息时代技术的爆炸性增长。然而，随着设备尺寸接近原子尺度，进一步取得进展变得越来越困难。这一挑战需要利用量子现象的新方法。利用量子特性的新型电子设备具有更好的设备可靠性和更低的功耗。量子技术也带来了自身的挑战。特别是，环境影响会破坏量子信息，纠错需要大量资源。由于其独特的性质，拓扑材料为解决这一问题提供了巨大的潜力。特别是，量子态受到对称性的拓扑保护，更不容易受到破坏。在这个项目中，将使用弹性应变而不是电场或磁场来控制设备中的电子态。与基于互补金属氧化物半导体的传统设备相比，逻辑门和其他电子设备预计更可靠，耗电量更少。互动式和参与性的教育推广计划将与研究项目相结合。其中包括《科学》博客写作以及材料和设备展品。这些外展工作将促进公众的科学素养，并提高当地K-12学生的科学鉴赏力。这反过来又会吸引这些学生在教育的早期阶段接触现代科学和技术。技术：这项合作研究项目涉及两类拓扑材料--拓扑晶体绝缘体(TCI)和魏尔半金属(WSM)，分别在其表面承载无质量的狄拉克费米子和具有一定手性的魏尔费米子的新型应变电子(或紧致内含子)纳米线器件。这些特殊的表面态或体态受到对称性的拓扑保护，对杂质、缺陷和无序具有很强的抵抗力。与传统的基于半导体的电子设备相比，利用这些量子/拓扑态的电子设备可能具有显著提高的可靠性和/或降低的功耗。这个项目的总体目标是研究和操纵在拓扑设备中使用可控弹性应变的狄拉克和韦尔费米子的奇异量子特性，以实现低功率、高可靠性的电子应用。与之前对大块晶体和薄膜的研究不同，拟议的研究将集中在纳米线/纳米带器件上，这些器件具有特殊的特性，可用于约束电子学的研究和应用。该项目的成功将建立在两个PI的现有合作、对拓扑材料的广泛熟悉以及在材料合成、器件制造、磁传输研究和电子系统理论建模方面的互补专业知识的基础上。应变驱动的拓扑相变和相关的量子输运性质的理论和实验相结合的研究将为电子系统中潜在的基础物理提供新的范例。这项拟议的研究也有望代表着建立一个新的研究领域--拓扑张力学--的关键一步：操纵具有可控弹性应变的拓扑准粒子。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical:Semiconductor technologies have fueled the explosive growth of information-age technologies over the last half century. Further advances, however, are becoming increasingly difficult as devices dimensions approach atomic scales. This challenge requires new approaches that harness quantum phenomena. Novel electronic devices that exploit quantum properties have the potential for better device reliability and lower power consumption. Quantum technologies bring their own challenges. In particular, environmental effects can corrupt quantum information and significant resources are required for error correction. Topological materials offer great potential to address this problem because of their unique properties. In particular, quantum states are topologically protected by symmetries and are less subject to corruption. In this project elastic strain rather than electric or magnetic fields will be used to control electronic states in devices. Logic gates and other electronic devices are expected to be more reliable and use less power than conventional devices based on complementary metal oxide semiconductors. Interactive and engaging educational outreach programs will be integrated with the research project. These include Science Blog writing and Materials and Device Exhibits. These outreach efforts will promote scientific literacy to the general public and improve science appreciation by local K-12 students. This in turn will attract such students to modern science and technology in the early stages of their education. Finally, the participation of underrepresented groups in scientific research will be enhanced.Technical:This collaborative research project concerns novel strain-electronic (or straintronic) nanowire devices built upon two classes of topological materials, topological crystalline insulators (TCIs) and Weyl semimetals (WSMs), which host massless Dirac fermions on their surfaces and Weyl fermions with definite chirality in their bulk, respectively. These extraordinary surface or bulk states are topologically protected by symmetries and are rather robust against impurities, defects and disorder. Electronic devices exploiting these quantum/topological states are likely to have significantly improved reliability and/or reduced power consumption relative to conventional semiconductor-based electronics. The overall objective of this project is to study and manipulate the exotic quantum properties of Dirac and Weyl fermions in topological devices utilizing controllable elastic strain towards low-power, highly reliable electronic applications. In contrast to previous studies of bulk crystals and thin films, the proposed research will focus on nanowire/nanoribbon-based devices that harbor exceptional features for straintronic studies and applications. The success of the project will be built on the two PIs' existing collaboration, extensive familiarity with topological materials, and complementary expertise on material synthesis, device fabrication, magneto-transport studies, and theoretical modeling of electronic systems. The combined theoretical and experimental studies of strain-driven topological phase transitions and associated quantum transport properties will offer new paradigms for fundamental, potentially exploitable physics in electronic systems. The proposed research is also anticipated to represent a key step in establishing a new research area, topological straintronics: the manipulation of topological quasi-particles with controllable elastic strain.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.