Electronic Thermal Transport in Nanoscale Conductors

纳米级导体中的电子热传输

• 批准号: 0933454
• 负责人: Li Shi
• 金额: $ 30万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933454&HistoricalAwards=false
• 关键词: Electronic; Thermal; Transport; Nanoscale; Conductors

0933454ShiThe Wiedemann-Franz (W-F) law describing thermal transport by electrons is a hallmark of success of the Sommerfeld theory. For electrons confined in one- or two-dimensional nanostructures, however, several intriguing phenomena can lead to the breakdown of the W-F law. These phenomena include strong correlation effects associated with increased electron-electron interaction, as well as electron localization. Intellectual Merit. This experimental study addresses a fundamental question regarding whether the Wiedemann-Franz Law is valid in low dimensional conductors. The scientific question being addressed is of a very fundamental nature, and one that will impact multiple disciplines. The experimental study examines electronic thermal transport in copper nanowires, quasi one-dimensional polyacetylene nanofibers, and two-dimensional graphene nanoribbons. The thermal conductivity, electrical conductivity, and Seebeck coefficient of these nanostructures are measured using nanofabricated suspended measurement devices at various temperatures. Chemical doping, electrical field effects, and the thermal Hall effect are employed to tune and determine the electronic thermal conductivity and isolate the lattice contribution. The validity of the W-F law is examined by analyzing the measured Lorenz number and its temperature dependence, and comparing the measurement results with the predictions of different transport theories. Broader Impacts. The nanostructures of interest are being considered for nanoelectronics, sensors, energy conversion, and thermal management applications, all of which will benefit from a better understanding of electronic thermal transport in these nanostructures. The research provides interdisciplinary education opportunities for graduate and undergraduate students. New example materials for a graduate and an undergraduate course in thermal science are being produced, as are new materials for three K-12 outreach activities designed to attract young girls to engineering professions, and to expose public school students and teachers in Texas to engineering principles.

0933454Shithe Wiedemann-Franz（W-F）描述电子热运输的法律是Sommerfeld理论成功的标志。但是，对于限制在一维纳米结构中的电子，几种有趣的现象可能导致W-F法律的崩溃。这些现象包括与电子电子相互作用增加以及电子定位有关的强相关效应。智力优点。这项实验研究解决了关于Wiedemann-Franz法律在低维导体中是否有效的基本问题。要解决的科学问题具有非常基本的性质，并且会影响多个学科。实验研究检查了铜纳米线，准一维聚乙二醇纳米纤维和二维石墨烯纳米纤维中的电子热传输。这些纳米结构的热导率，电导率和塞更系数是在各种温度下使用纳米制造的悬浮测量装置测量的。化学掺杂，电场效应和热厅效应用于调整并确定电子导热率并隔离晶格的贡献。通过分析测得的洛伦兹数及其温度依赖性，并将测量结果与不同运输理论的预测进行比较，可以检查W-F法律的有效性。更广泛的影响。正在考虑使用感兴趣的纳米结构用于纳米电子，传感器，能量转换和热管理应用，所有这些都将受益于对这些纳米结构中电子热传输的更好理解。这项研究为研究生和本科生提供了跨学科的教育机会。正在制作研究生和热科学的本科课程的新示例材料，以及三种K-12外展活动的新材料，旨在吸引年轻女孩进入工程专业，并将德克萨斯州公立学校的学生和老师暴露于工程原则。