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理学大师论坛——Baowen Li:Anomalous phonon/heat transport in low dimensional micro/nano systems(5月28日下午15:00)

编辑:phyjd 时间:2019年05月21日 访问次数:463

题目:Anomalous phonon/heat transport in low dimensional micro/nano systems

报告人:Baowen Li Department of Mechanical Engineering, University of Colorado

地点: 教十二—201

时间: 528日,周二,15:00-16:00

Abstract

When system dimension and size go down, many interesting phenomena can happen. Both experimental and numerical works in recent years have shown that phonon/heat transport in low (quasi 1D and 2D) dimensional micro 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 the Fourier law;

(b) heat transports may break down the reciprocal principle, 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 phononic thermal devices like thermal diode and thermal transistor, which lay the foundation of a new emerging field – phononics.

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

References:

  1. X. K Gu, et al, Rev. Mod. Phys 90 (4), 041002 (2018)

  2. X-F Xu et al, Nat Comm 10, 1038 (2014).

  3. S Liu et al, Phys Rev. Lett 112, 040601 (2014).

  4. N-B Li et al, Rev Mod Phys 84 (3), 1045 (2012).

Bio about the speaker:

Dr. Li received B. S from Nanjing University, M. Sci from Institute of Acoustics, the Chinese Academy of Science, and Ph. D from Oldenburg University, Germany in 1985, 1989 and 1992, respectively. He joined National University of Singapore (NUS) as assistant professor in 2000, and become full professor in 2007 and worked there until 2014. He has been 2014/2015 Russell Severance Springer Professor at Department of Mechanical Engineering, UC Berkeley. In August 2015, he joined Department Mechanical Engineering, University of Colorado Boulder as the Rennie 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 in Rev. Mod. Phys and 30 in Phys Rev. Lett. Delivered more than 220 plenary, keynote, invited/seminar talks. He is APS fellow (2013), and recipient of numerous awards including 2005 National Science Award, Singapore, and 2005 OCPA’s (International Organization of Chinese Physicists and Astronomers) Asia Achievement Award and 2014/2015 Springer Professorship at University of California, Berkeley. 2017 Brillouin Medal from International Phononics Society. He is selected member of Academy of Europaea since 2017.

His currently research activities include but not limited to: fundamental theory and measuring techniques of phonon/heat transport, phononic thermal devices, thermal metamaterials, topological and quantum phononics, quantum sensors, and complex networks etc.


欢迎老师和同学参加!