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****随着电子结构的大小继续减小，电子运动的经典视图基于相互作用的电子状态和波形，转化为完全量子图片。要了解这张量子图片，我们需要可视化电子的位置并了解它们的移动方式。 液体-HE冷却的扫描探针显微镜（SPM）用于使用库仑封锁光谱法提取半导体纳米结构内各个电子状态的能量和波形。 该样品是INAS/INP纳米线中的长而薄的INAS量子点，其中包含一排形成一维电子气体的电子。 可以通过用SPM尖端在局部张开波函数来成像，SPM尖端充当可移动的门，并在沿点移动时记录量子状态的能量变化。 该小组计划随着电子数量的增加，调查了从Wigner晶体到Luttinger液体的预测过渡。研究和教育将通过培训研究生的培训，并通过针对本科生的夏季研究经验进行整合。 我们对电子运动的经典视图转化为基于相互作用的电子状态和波形的量子图片。 正在开发一种技术来测量单个电子状态的能量并使用冷却的扫描探针显微镜（SPM）绘制波形。 一排电子被固定在一个在INAS/INP纳米线中形成的长量子点中 - 纳米线是如此狭窄，以至于电子必须对齐，一个接一个。 单个电子状态的能量是使用库仑阻滞光谱测量的 - 电流才能在添加或去除电子滴度零时才流经点。 通过用带电的SPM尖端将波函数缩起，并在尖端沿点移动时测量量子状态的能量变化来映射波函数。 这样，SPM可以可视化量子图片，以便从纳米结构开发新型的量子设备。研究和教育将通过培训研究生的培训以及本科生的夏季研究经验来整合。