Excited-State Properties of Electrostatically Doped Low-Dimensional Structures

静电掺杂低维结构的激发态特性

• 批准号: 1207141
• 负责人: Li Yang
• 金额: $ 27.53万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207141&HistoricalAwards=false
• 关键词: Excited; State; Properties; Electrostatically; Doped

TECHNICAL SUMMARYThis award supports computational and theoretical research and education to study doping effects on excited-state properties of low-dimensional structures of broad interest, including silicon nanowires, graphene and electrically gated bilayer graphene. Because of the geometry of these structures and the associated divergence of the electronic density of states close to the band edge, electrostatically doped free carriers can dramatically change the electronic screening of many-electron interactions. As a result, an even small amount of doping may substantially change the excited-state properties, such as the quasiparticle band gap and optical properties, making doping an efficient tool to tune the intrinsic electronic structure of low-dimensional materials in addition to its usual role of providing free carriers. The variation of many-electron effects may also modify the spin singlet-triplet splitting which would change the luminescence properties with possible application to quantum information technology. The research involves using density functional theory based methods along with GW and the solution of the Bethe-Salpeter equation.This award also supports educational activities, including a new course, 'First-Principles Calculations and Their Applications to Nanostructures,' in Washington University. Additional activities include a series of seminars for interested researchers from institutes nearby to introduce cutting-edge first-principles approaches and their applications to the nanotechnology. NONTECHNICAL SUMMARYThis award supports computational and theoretical research and education to investigate the properties of very tiny wires that are little more than a few atoms wide and single-atom thick carbon sheets known as graphene. The PI will use advanced computational methods that aim to predict properties of structures of atoms and materials starting from knowledge of their constituent atoms. Of particular interest are properties that involve how well materials and structures of atoms absorb or emit light. An aim of the work is to determine how the addition and removal electrons from the quantum wires or graphene can be used to design the quantum mechanical states of quantum wires and graphene. This project contributes to the knowledge base including methods and software upon which future device technologies will be based. Specific aspects of the work contribute to the design of photovoltaic devices for the efficient conversion of light to electricity. This award also supports educational activities, including a new course, 'First-Principles Calculations and Their Applications to Nanostructures,' in Washington University. Additional activities include a series of seminars for interested researchers from institutes nearby to introduce cutting-edge first-principles approaches and their applications to the nanotechnology.

技术摘要这一奖项支持计算和理论研究和教育，以研究对广泛关注的低维结构（包括硅纳米线，石墨烯和电气封闭的双层石墨烯）的兴奋剂效应。由于这些结构的几何形状以及靠近带边缘的电子密度的相关差异，静电掺杂的自由载体可以极大地改变许多电子相互作用的电子筛选。结果，甚至少量的掺杂可能会显着改变激发态性能，例如准颗粒带隙和光学特性，使掺杂成为有效的工具，以调整低维材料的固有电子结构，此外其通常具有提供自由载体的作用。多电子效应的变化也可能会改变自旋单线 - 三曲线分裂，从而改变发光特性，并可能应用于量子信息技术。该研究涉及使用基于密度功能理论的方法以及GW以及伯特 - 盐分方程的解决方案。该奖项还支持华盛顿大学的教育活动，包括新课程，包括“第一原则计算及其在纳米结构中的应用”。其他活动包括一系列针对附近学院的感兴趣的研究人员进行的研讨会，以引入尖端的第一原理方法及其对纳米技术的应用。非技术摘要这一奖项支持计算和理论研究和教育，以研究非常微小的电线的性质，这些电线的特性仅超过几个原子宽和单原子厚的碳片，称为石墨烯。 PI将使用先进的计算方法，旨在预测其成分原子知识开始的原子和材料结构的特性。特别感兴趣的是涉及原子的材料和结构吸收或发光的质量。这项工作的目的是确定如何使用量子线或石墨烯中的添加和去除电子来设计量子线和石墨烯的量子机械状态。该项目有助于知识库，包括未来设备技术将基于的方法和软件。工作的特定方面有助于设计光伏设备，从而有效地转换为电力。该奖项还支持华盛顿大学的新课程，包括新课程的“第一原理计算及其对纳米结构的应用”。其他活动包括一系列针对附近学院的感兴趣的研究人员进行的研讨会，以引入尖端的第一原理方法及其对纳米技术的应用。