Phonon Heat Transport and Mechanical Oscillations in Mesoscopic Systems

介观系统中的声子热传输和机械振荡

• 批准号: 9873573
• 负责人: Michael Cross
• 金额: $ 27万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-15 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9873573&HistoricalAwards=false
• 关键词: Phonon; Heat; Transport; Mechanical; Oscillations

9873573CrossThis award supports theoretical research and education that aims to investigate the transport of heat by phonons and mechanical oscillations in fabricated structures of GaAs and silicon on the 10-100 nm length scale. Recent advances in microfabrication techniques have allowed the construction of suspended, free-standing structures of insulating or doped GaAs or silicon. Portions of these structures are isolated from the substrate so that the only thermal pathway to the environment is through the suspension "beams." These beams are defined lithographically, so they can be designed to allow measurements of thermal transport at the mesoscopic scale. Thermal pathways of rectangular cross-section 200 X 300 nm and length 5m have already been constructed, and much smaller widths seem feasible. The mechanical oscillations of these structures can also be studied experimentally. These advances promise the first systematic investigation of heat transport by phonons in mesoscopic systems, and further development in the study of mechanical oscillations in mesoscopic systems which is poorly understood. The PI proposes a theoretical attack on these problems. The PI plans to extend their recent work based on the Landuaer-Buttiker formalism. Realistic models of phonons that will allow the quantitative prediction of thermal transport will be used and the effects of scattering by geometry, surface roughness, and material disorder will be included. Electron-phonon interaction effects, which can also be studied in experimental geometries, will be investigated. At low temperatures, the modes containing the thermal energy become the mechanical oscillation modes of the suspended structures, so that studies of heat transport and dissipation in mechanical oscillators becomes closely related. Thus it is possible to extend the theoretical investigation to mesoscopic oscillators, and in particular the Q of such oscillators.%%%This award supports research and education in an area that is both fundamental science and related to MEMS (microelectromechanical systems). The PI will use state of the art techniques to study vibrations and oscillations and the flow of heat in mechanical systems fabricated from silicon and other materials on micron and sub-micron length scales.***

该奖项支持理论研究和教育，旨在研究10- 100nm长度尺度上GaAs和硅的制造结构中声子的热传递和机械振荡。微加工技术的最新进展使绝缘或掺杂砷化镓或硅的悬浮、独立结构的构建成为可能。这些结构的一部分与基板隔离，因此唯一的热途径是通过悬挂“梁”。这些光束是用光刻技术定义的，因此它们可以被设计成允许在介观尺度上测量热传输。已经构建了长度为5m的矩形截面200 X 300 nm的热路径，更小的宽度似乎是可行的。这些结构的力学振荡也可以通过实验来研究。这些进展有望首次系统地研究介观系统中声子的热输运，并进一步发展对介观系统中机械振荡的研究。PI对这些问题提出了理论攻击。PI计划扩展他们最近基于landuer - buttiker形式主义的工作。将使用声子的实际模型来定量预测热输运，并将包括几何散射、表面粗糙度和材料无序性的影响。电子-声子相互作用效应，也可以研究在实验几何，将进行研究。在低温下，包含热能的模态成为悬架结构的机械振动模态，使得热在机械振子中的传递和耗散的研究变得密切相关。因此，有可能将理论研究扩展到介观振子，特别是这种振子的Q。该奖项支持基础科学和MEMS（微机电系统）相关领域的研究和教育。PI将使用最先进的技术来研究由硅和其他材料在微米和亚微米长度尺度上制造的机械系统中的振动和振荡以及热流