讲座题目：Anomalous phonon/heat transport in lowdimensional micro/nano systems

主讲人：Baowen Li 教授

主持人：刘宗华 教授

开始时间：2019年4月22日下午13:30

讲座地址：闵行校区物理楼226报告厅

报告人简介：

    Prof. Li has been 2014/2015 Russell Severance Springer Professor atDepartment of Mechanical Engineering, UC Berkeley. In August 2015, he joinedDepartment of Mechanical Engineering, University of Colorado Boulder as theRennie Family Endowed Professor. He is one of the pioneers in an emerging field– Phononics. He has authored and co-authored over 330 papers including 2 inRev. Mod. Phys and 30 in Phys Rev. Lett. Delivered more than 220 plenary,keynote, invited/seminar talks. He is APS fellow (2013), and recipient ofnumerous awards including 2005 National Science Award, Singapore, and 2005OCPA’s (International Organization of Chinese Physicists and Astronomers) AsiaAchievement Award and 2014/2015 Springer Professorship at University ofCalifornia, Berkeley. 2017 Brillouin Medal from International PhononicsSociety. He is selected member of Academy of Europaea （欧洲科学院院士）since 2017.

报告内容简介：

    When system dimension and size go down, many interestingphenomena can happen. Both experimental and numerical works in recent yearshave shown that phonon/heat transport in low (quasi 1D and 2D) dimensionalmicro systems and nano structures like nanotube, nanowire, polymer chain,graphene, and other 2D materials show anomalous behavior:

(a) heat conduction due to phonons does not follow theFourier law;

(b) heat transports may break down the reciprocalprinciple, namely heat flows asymmetrically.

(c) negative differential thermal resistance will arise,namely the larger the temperature drops, the smaller the heat current.

Issues (b) and (c) can be used to build up useful phononicthermal devices like thermal diode and thermal transistor, which lay thefoundation of a new emerging field – phononics.

In this talk, I will discuss theunderlying physical mechanism of these anomalous heat/phonon transport. Inparticular, I will discuss how the anomalous thermal transport - a macroscopicphenomenon – is connected with the anomalous energy diffusion- a microscopic process.

References:

1.X. K Gu, et al, Rev.Mod. Phys90 (4), 041002 (2018)

2.X-F Xu et al, NatComm10, 1038 (2014).

3.S Liu et al, PhysRev. Lett112, 040601 (2014).

4.N-B Li et al, Rev ModPhys84 (3), 1045 (2012).