Two dimensional atomic crystals under strain

非技术描述：二维原子晶体是层状材料的基石，具有良好的电/光性能，这些性能受到其结构的强烈影响。这些材料是通过强烈的化学键形成的，它们可以在原子上很薄，但像晶体一样具有弯曲的能力。了解晶体形变(应变)如何改变它们的电子和电荷输运性质既有趣又重要。基于这样的理解，晶格形变可能被用来获得更好的电子性质，并为低维物理研究创造新的材料体系。本项目研究应变对二维原子晶体在其纳米机电设备中电子和电荷传输特性的影响，其中应变可以被独立地调谐和精确地表征。该项目解决了一个高度活跃的研究领域中的一些关键科学和技术问题。它还为研究生提供了在PI的石溪实验室和国家实验室环境中的研究经验。来自石溪大学不同学生群体的本科生和来自大纽约地区的高中生将被邀请在研究中发挥积极作用。为了扩大公众对科学的兴趣，研究小组将播放学生在实验室进行研究的原创视频，并介绍基本实验研究技术。技术说明：二维原子晶体是通过强烈的化学键形成的，使其具有柔韧性和可伸缩性。因此，晶格形变可能被用来实现更有利的电子性质，并为低维物理研究创造新的材料体系。该项目正在开发一种具有大应变可调谐和输运测量能力的纳米机电谐振器装置方案，通过该方案研究和关联机械和电荷输运特性。这种方法被应用于二维原子晶体，包括(但不限于)单层和双层石墨烯、磷烯和ZrTe5。研究小组重点研究了机械变形(包括单轴、剪切和三轴应变)对这些二维材料中的载流子散射、谷极化、能带结构调整和拓扑转变的影响。该项目促进了对新型二维材料基本物理性质的理解，以及通过调节其电子性质来研究新型二维物理。晶格结构和/或对称性的改变可以有效地创造新的人工材料体系，使人们能够研究传统材料无法实现的新的物理现象。该提案主要集中在电荷传输研究上，直接涉及电子器件的制造和测量。因此，它进一步推动了应变可调电子学的概念，超越了以前主要基于光学和本地探测研究的努力。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。

Non-Technical Description:Two-dimensional atomic crystals, the building blocks for layered materials, have promising electrical/optical properties that are strongly affected by their structures. Formed through strong chemical bonds, these materials can be atomically thin yet act like a crystal with the ability to bend. It is both interesting and important to understand how the crystal deformation (strain) may modify their electronic and charge transport properties. Based on such understanding, lattice deformation may be used for better electronic properties and to create novel material systems for the study of low dimensional physics. This project studies the impact of strain on the electronic and charge transport properties of two-dimensional atomic crystals in their nanoelectromechanical devices, where strain can be independently tuned and accurately characterized. This project addresses some of the key scientific and technological issues in a highly active research area. It also provides graduate students with research experience both in the PI's Stony Brook laboratory and in national laboratory settings. Undergraduate students drawn from the diverse student body of Stony Brook University and high school students from the greater New York region will be brought in to play active roles in the research. To widen the general public interest in sciences, the research team will broadcast original videos on student research in the lab, and introductions to basic experimental research techniques.Technical Description:Two-dimensional atomic crystals are formed through strong chemical bonds which render them flexible and stretchable in nature. As a result, lattice deformation may be utilized to achieve more favorable electronic properties and to create novel material systems for the study of low dimensional physics. The project is developing a nanoelectromechanical resonator device scheme with large strain tunability and transport measurement capability, through which both the mechanical and charge transport properties are studied and correlated. This approach is applied to two-dimensional atomic crystals including (but not limited to) single- and bi-layer graphene, phosphorene, and ZrTe5. The research team focuses on the impact of mechanical deformation (including uniaxial, shear and triaxial strains) on charge carrier scattering, valley polarization, band structure tuning, and topological transitions in these two-dimensional materials. The project advances the understanding in the fundamental physical properties of novel two dimensional materials and in modulating their electronic properties to study novel two-dimensional physics. Modification of lattice structure and/or symmetry can effectively create new artificial material systems which allow the study of novel physical phenomena inaccessible in conventional materials. This proposal, which focuses mainly on charge transport studies, directly addresses fabrication and measurement of the electronic devices. Hence, it further advances the concept of strain-tunable electronics beyond the previous efforts which are mainly based on optical and local probe studies.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.