7月10日Vanderbilt University李德玉教授学术报告

发布者:钟芳发布时间:2017-07-08

    我们有幸邀请到Vanderbilt University的李德玉教授来访并做关于界面声子动力学方面的报告,李德玉教授是纳米尺度热输运方面的专家,尤其在界面热导方面做了诸多前瞻性的工作,本次报告摘要如下,欢迎各位老师和课题组成员参加!

时间:7月10日(周一)上午10:00
地点:唐仲英楼B501

Abstract:    

Nanoscale thermal transport has attracted significant attention over the past two decades because of both fundamental scientific interest and important engineering applications. For semiconductors and insulators, phonons are the dominant energy carriers and interactions between phonons and surfaces/interfaces play a key role in energy transport. From studying thermal transport through various individual nanostructures and their contacts, we have obtained several new insights into the phonon dynamics at surfaces and interfaces, which could have important implications in engineering the effective properties of nanostructured materials. Through measuring the thermal conductivity of silicon nanowires and nanoribbons, we show that when the surface-area-to-volume ratio reaches a critical value, size effects beyond phonon-boundary scattering becomes important. Further, studies on kinked boron carbide nanowires disclose how phonons transmit through a nanoscale kink, which provides new opportunities for tuning materials’ thermal conductivity. Examination of the contact thermal conductance between two individual multi-walled carbon nanotubes reveal an interesting diameter dependence, which involves intriguing underlying physics. Finally, comparison of the thermal conductivity of single and double boron nanoribbons suggests that there are two separate specularity parameters at interfaces for transmitted and reflected phonons, respectively. These new understandings could lead to novel materials design for desired effective thermal properties.