Imaging Electron States in Nanostructures

纳米结构中的电子态成像

• 批准号: 1105341
• 负责人: Robert Westervelt
• 金额: $ 40.5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105341&HistoricalAwards=false
• 关键词: Imaging; Electron; States; Nanostructures

****Technical Abstract****As the size of electronic structures continues to decrease, the classical view of electron motion transforms into a fully quantum picture based on interacting electron states and wavefunctions. To understand this quantum picture, we need to visualize where electrons are and understand how they move. A liquid-He cooled scanning probe microscope (SPM) is used to extract both the energy and the wavefuction of individual electron states inside a semiconductor nanostructure, using Coulomb blockade spectroscopy. The sample is a long, thin InAs quantum dot in an InAs/InP nanowire, which contains a row of electrons that form a one-dimensional electron gas. The wavefunction can be imaged by locally denting the wavefunction with the SPM tip, which acts as a moveable gate, and recording the resulting change in energy of the quantum state as the tip is moved along the dot. The group plans to investigate the predicted transition from a Wigner crystal to a Luttinger liquid as the number of electrons is increased. Research and education will be integrated through the training of graduate students, and through summer research experiences for undergraduate students.****Non-Technical Abstract****As the size of electronic devices decreases, quantum mechanics becomes increasingly important. Our classical view of electron motion transforms into a quantum picture based on interacting electron states and wavefunctions. A technique is being developed to measure the energy of individual electron states and map their wavefunctions using a cooled scanning probe microscope (SPM). A row of electrons is held inside a long quantum dot formed in an InAs/InP nanowire - the nanowire is so narrow that the electrons must line up, one after the other. The energy of a single electron state is measured using Coulomb blockade spectroscopy - current can flow through the dot only when the energy required to add or remove an electron drops to zero. The wavefunction is mapped by denting the wavefunction with the charged SPM tip, and measuring the change in energy of the quantum state as the tip is moved along the dot. In this way, the SPM can visualize the quantum picture in order to develop new types of quantum devices from nanostructures. Research and education will be integrated through the training of graduate students, and through summer research experiences for undergraduate students.

* 技术摘要 * 随着电子结构的尺寸不断减小，电子运动的经典观点转变为基于相互作用的电子态和波函数的完全量子图像。为了理解这个量子图像，我们需要想象电子在哪里，并理解它们如何运动。 液氦冷却的扫描探针显微镜（SPM）被用来提取能量和波函数的单个电子状态内的半导体纳米结构，使用库仑阻塞光谱。 样品是InAs/InP纳米线中的长而薄的InAs量子点，其包含形成一维电子气的一排电子。 波函数可以通过用SPM尖端局部凹陷波函数来成像，SPM尖端充当可移动的门，并且当尖端沿沿着点移动时记录量子态的能量的结果变化。 该小组计划研究随着电子数量的增加，从Wigner晶体到Luttinger液体的预测转变。研究和教育将通过研究生的培训，并通过本科生的夏季研究经验相结合。非技术摘要 * 随着电子设备尺寸的减小，量子力学变得越来越重要。 我们对电子运动的经典观点转变为基于相互作用的电子态和波函数的量子图像。 正在开发一种技术，以测量单个电子态的能量，并使用冷却扫描探针显微镜（SPM）映射其波函数。 InAs/InP纳米线中形成的长量子点内有一排电子-纳米线非常窄，电子必须一个接一个地排列。 单电子态的能量是使用库仑阻塞光谱测量的-只有当添加或移除电子所需的能量降到零时，电流才能流过点。 波函数的映射是通过用带电的SPM尖端凹陷波函数，并测量当尖端沿着点移动时量子态的能量变化。 通过这种方式，SPM可以可视化量子图像，以便从纳米结构开发新型量子器件。研究和教育将通过研究生的培训，并通过本科生的夏季研究经验相结合。