Carrier, Phonon and THz Dynamics in Narrow Gap and Carbon Based Nanostructures

该奖项支持理论凝聚态物理学的综合研究，教育和推广活动。 本项目的目标是研究和模拟：1）载流子-载流子，2）载流子-声子和3）载流子-光子在窄禁带化合物半导体异质结构中的相互作用，如锑化铟/锑化铝铟量子威尔斯和碳基纳米结构。 这些材料有望用于我们的下一代高速晶体管和探测器。 虽然看起来非常不同，但它们具有共同的特征，1）能量-波矢量关系对于大波矢量是线性的，以及2）高室温迁移率。该项目涉及半导体纳米结构随时间变化的光学和输运性质的计算和建模。 重点包括：1.）单壁碳纳米管和石墨烯。 虽然这些材料的不寻常的DC输运特性以前已经研究过，但它们的动力学特性被证明同样有趣。将对碳纳米管、石墨烯和石墨烯纳米带中的相干声子进行建模。窄禁带InSb异质结。 由于它们的有效质量小，g因子大，这些材料是快速晶体管或新型自旋电子器件的优秀候选者。这些材料的随时间变化的光学性质将被计算和建模，以获得有关的电子和磁状态和输运性质的信息。 理论与实验的紧密结合将提供对载流子、自旋和声子动力学的理解。该项目的研究生将在纳米科学的前沿研究课题中进行培训，包括半导体物理、量子光学、纳米管和纳米粒子物理以及输运理论。学生将有机会参与并与美国和国际研究人员互动。 他们的工作结果将有助于确定哪些材料是未来高速纳米电子器件和探测器的最佳材料。 非技术总结该奖项整合了理论凝聚态物理学的研究，教育和推广。 该项目的动机是研究和理解两类新的纳米结构材料的特性，这些材料是下一代高速晶体管，光源和探测器的有前途的材料。 这些材料是：1.）由碳制成的结构类似于纳米尺度的带状物或管状物-比人类头发的宽度小一万倍-称为碳纳米管和碳纳米带，2。石墨烯，其是单层碳原子，其类似于纳米级上的铁丝网，其中碳原子排列在顶点处，以及3.）纳米结构由元素铟和锑组成的化合物制成，称为锑化铟。虽然这些材料乍看起来可能非常不同，但它们具有一些共同的特性。特别是，它们的电子性质非常相似，在室温下，石墨烯和锑化铟纳米结构中的电子可以比几乎任何其他材料（包括硅和砷化镓）中的电子更快，更容易移动。 这为基于这两种材料的晶体管提供了希望，有朝一日可能会取代目前用于计算机的硅技术晶体管。 PI将研究碳和锑化铟纳米结构中的电子如何与1相互作用和散射。其他电子，2.）在纳米结构中移动的原子和3.）电磁辐射 与电磁辐射的相互作用是特别有趣的，因为结果表明，这些材料可能被用来产生和检测电磁辐射在太赫兹部分的频谱位于微波和红外光之间。 太赫兹辐射是非电离的;有一天，这种辐射源可能会取代医学成像中的X射线，并且有害副作用更少。该项目的研究生将接受纳米科学前沿研究课题的培训，包括半导体物理学、量子光学、纳米管和纳米带物理学以及传输理论领域。学生将有机会参与并与美国和国际研究人员互动。 他们的工作结果将有助于确定哪些材料是未来高速纳米电子器件和探测器的最佳材料。

TECHNICAL SUMMARYThis award supports integrated research, education and outreach activities in theoretical condensed matter physics. The goal of this project is to study and model: 1) carrier-carrier, 2) carrier-phonon and 3) carrier-photon interactions in narrow gap compound semiconductor heterostructures such as indium antimonide/aluminum indium antimonide quantum wells and carbon based nanostructures. These materials are promising for our next generation of high speed transistors and detectors. Although seemingly very different, they share common features, 1) an energy-wavevector relationship that is linear for large wavevector, and 2) high room temperature mobilities. This project involves calculating and modeling the time-dependent optical and transport properties of semiconductor nanostructures. Foci include:1.) Single-walled carbon nanotubes and graphene. While the unusual DC transport properties of these materials have been previously studied, their dynamical properties are proving to be equally interesting. Coherent phonons in carbon nanotubes, graphene and graphene nanoribbons will be modeled.2.) Narrow gap InSb heterostructures. With their small effective masses and large g-factors, these materials are excellent candidates for fast transistors or novel spintronic devices. The time-dependent optical properties of these materials will be calculated and modeled to gain information about the electronic and magnetic states and transport properties. Close coupling between theory and experiment will provide an understanding of the carrier, spin, and phonon dynamics.Graduate students on this project will be trained in forefront research topics in the nanosciences including the fields of semiconductor physics, quantum optics, nanotube and nanoribbon physics, and transport theory. The students will get a chance to participate and interact with researchers both in the U.S. and also internationally. Results of their work will help determine which materials are optimal for future high speed nano-electronic devices and detectors. NON-TECHNICAL SUMMARYThis award integrates research, education and outreach in theoretical condensed matter physics. The motivation of the project is to study and understand properties of two new classes of nanostructured materials that are promising materials for the next generation of high speed transistors, and optical sources and detectors. These materials are: 1.) structures made of carbon that resemble ribbons or tubes of nanoscale dimensions - some ten thousand times smaller than the width of a human hair - called carbon nanotubes and carbon nanoribbons, 2.) graphene which is a single layer of carbon atoms which resembles chickenwire on the nanoscale with carbon atoms arranged at the vertices, and 3.) nanoscale structures made of a compound composed of elements indium and antimony, called indium antimonide.While these materials at first seem may seem very different, they share several common properties. In particular, their electronic properties are very similar and at room temperature, electrons in graphene and indium antimonide nanostructures can move faster and more easily than electrons in almost any other material including silicon and gallium arsenide. This offers hope that transistors based on these two materials may one day replace transistors based on silicon technology, currently used in today's computers. The PI will investigate how electrons in carbon and indium antimonide nanostructures interact and scatter with 1.) other electrons, 2.) atoms that are moving in the nanostructures and 3.) electromagnetic radiation. The interaction with electromagnetic radiation is particularly intriguing since results suggest that these materials might be used to generate and detect electromagnetic radiation in the tera Hertz part of the spectrum which lies between microwaves and infrared light. Tera Hertz radiation is non-ionizing; one day sources of this radiation may replace X-rays in medical imaging with fewer harmful side effects.Graduate students on this project will be trained in forefront research topics in the nanosciences including the fields of semiconductor physics, quantum optics, nanotube and nanoribbon physics, and transport theory. The students will get a chance to participate and interact with researchers both in the U.S. and also internationally. Results of their work will help determine which materials are optimal for future high speed nano-electronic devices and detectors.