Collaborative Research: Spin-electronic Dynamics in Three Terminal Couples Quantum Structures

合作研究：三端耦合量子结构中的自旋电子动力学

• 批准号: 0223817
• 负责人: Eric Altman
• 金额: $ 20.54万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0223817&HistoricalAwards=false
• 关键词: Collaborative; Research; Spin; electronic; Dynamics

Eric I. Altman, Yale University"Spin-electronic Dynamics in Three Terminal Coupled Quantum Structures"This project focuses on exploring enabling technologies to allow the spin degree of freedom to be used as the controlling mechanism for quantum communication and computing. The principal investigators will fabricate and study coupled quantum-dot (QD) systems consisting of closely spaced III-V semiconductor, gallium arsenide (GaAs) quantum dots controlled by separated electrodes. The systems will be designed to transmit spin charges into QDs and to couple them in the neighboring dots by exchange interaction. Such a system is the first step toward building quantum logic gates, because the spin of one dot affects the electronic charge transport in the other dots by the exchange coulomb blockage effect. The spin states and the degree of coupling between the quantum dots can also be controlled by applied magnetic and/or electric fields. Magnetic contacts will serve as spin sources to provide carriers with particular spin orientation. The tunneling of these carriers through a particular dot will depend on the available spin state in the dot. This provides a convenient and practical way of determining the spin orientation of a particular dot and thus the variation of the spin in this dot after a certain time interval. Studying the spin dynamics in the context of manipulating and controlling individual spin states in each dot, and collectively in coupled quantum dots provides basic technology for fabricating quantum transistors and logic gates for quantum computing and communication devices. Successful fabrication of coupled dot systems requires employing state of the art synthetic methods at SUNY Binghamton. The fabrication of electrode structures at nanometer scales will use lithography on metallic thin films. The preparation of semiconductor quantum dots, such as GaAs, in the nanometer scales will utilize various synthetic, processing and assembling strategies. Methods will also be developed to produce GaAs:Mn nanoparticles; the manganese (Mn) doping can enhance spin state operating temperature in quantum dots. These semiconductor nanoparticles will be characterized using spectroscopic and microscopic techniques at both Yale and Binghamton. The spin charge exchange interaction between neighboring QDs will be studied by producing highly monodispersed III-V semiconductor nanoparticles self-assembled in a narrow gap about hundreds of nanometers wide between two metallic electrodes made by lithography. The study of detailed tunneling characteristics as a function of temperature and bias will be carried out in a magnetic cryostat at Binghamton. At Yale, scanning tunneling microscopy will be used to characterize the size, morphology, and electronic properties of the nanoparticles and their positioning between the electrodes. Magneto-infrared spectroscopy will be carried out on self-assembled semiconductor nano-particle arrays to examine spin exchange coupling between QDs. Broader Impact: This research will strongly impact future technologies in new functional devices based on spin degree of freedom, particularly providing assistance to the development of three-terminal spin field-effect-transistors using the developed techniques. These activities will allow the graduate students involved to learn and prepare themselves to become future technologists for developing next generation communication and computing devices. The integration of the nanostructure and novel computing technology into the curricula will provide interdisciplinary experiences for better career training for the students involved.

埃里克岛Altman，耶鲁大学“三端耦合量子结构中的自旋电子动力学”该项目的重点是探索使能技术，使自旋自由度用作量子通信和计算的控制机制。 主要研究人员将制造和研究耦合量子点（QD）系统，该系统由紧密间隔的III-V族半导体、由分离电极控制的砷化镓（GaAs）量子点组成。该系统将被设计为将自旋电荷传输到量子点中，并通过交换相互作用将它们耦合到相邻的量子点中。 这样的系统是构建量子逻辑门的第一步，因为一个点的自旋会通过交换库仑阻塞效应影响其他点的电荷传输。 量子点之间的自旋状态和耦合程度也可以通过施加的磁场和/或电场来控制。 磁性接触将用作自旋源以提供具有特定自旋取向的载流子。 这些载流子通过特定点的隧穿将取决于点中可用的自旋状态。 这提供了确定特定点的自旋取向并因此确定该点在特定时间间隔之后的自旋变化的方便且实用的方式。 在操纵和控制每个点中的各个自旋态以及耦合量子点中的集体自旋态的背景下研究自旋动力学，为制造用于量子计算和通信设备的量子晶体管和逻辑门提供了基础技术。成功制造耦合点系统需要在纽约州立大学宾厄姆顿分校采用最先进的合成方法。 纳米尺度的电极结构的制造将使用金属薄膜上的光刻。 半导体量子点的制备，如GaAs，在纳米尺度上，将利用各种合成，加工和组装策略。 还将开发生产GaAs：Mn纳米颗粒的方法;锰（Mn）掺杂可以提高量子点中的自旋态工作温度。 这些半导体纳米粒子将在耶鲁大学和宾厄姆顿大学使用光谱和显微技术进行表征。 相邻量子点之间的自旋电荷交换相互作用将通过产生高度单分散的III-V族半导体纳米粒子在由光刻制成的两个金属电极之间的约数百纳米宽的窄间隙中自组装来研究。 详细的隧道特性作为温度和偏置的函数的研究将在宾厄姆顿的磁低温恒温器中进行。 在耶鲁大学，扫描隧道显微镜将用于表征纳米粒子的大小，形态和电子特性及其在电极之间的定位。 磁红外光谱将在自组装的半导体纳米颗粒阵列上进行，以检查量子点之间的自旋交换耦合。更广泛的影响：这项研究将对基于自旋自由度的新功能器件的未来技术产生重大影响，特别是为使用所开发技术开发三端自旋场效应晶体管提供帮助。 这些活动将使参与的研究生学习和准备自己成为未来的技术专家，开发下一代通信和计算设备。将纳米结构和新的计算技术融入课程将为相关学生提供更好的职业培训提供跨学科的经验。