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Phononics and Thermal Metamaterials

Event Details

Event Dates: 

Thursday, October 15, 2015 - 12:00pm

Seminar Location: 

  • Duane Physics Room G126

Speaker Name(s): 

Baowen Li

Speaker Affiliation(s): 

University of Colorado Boulder
Seminar Type/Subject

Scientific Seminar Type: 

  • Condensed Matter Seminar

Event Details & Abstract: 

About a decade ago, we proposed a thermal diode model to rectify heat flux due to phonons in nanoscale [1]. A great progress has been achieved in this rapid developing field, including the experimental realization of solid-state thermal rectifier, thermal transistor model, and a new emerging field – Phononics [2].

In the first part of the talk, I will give an overview of past years’ development in this direction. Emphasis will be given on the fundamental principle of thermal diode, and the extension of thermal diode concept to control other energy forms including elastic energy, acoustic waves, heat carried by electrons, photons and magnons etc. I will also present our recently developed experimental technique – Electron beam heating method- to profile the thermal resistance alone a nanowire with a spatial resolution of 20 nm [3]. Using this technique, we are able to map the thermal conductivity along a heterostructured nanowire and the interfacial thermal resistance across a semiconductor/metal interface embedded in the heterostructured nanowires.

In the second part, I will talk about the thermal metamaterials [4-6] that can be used to realize many interesting functions like thermal cloaking, thermal concentrating, and even thermal inverting, etc.

References:

1.     B Li et al, Phys Rev. Lett  94, 114101 (2004);

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

3.     D Liu et al, Nano Lett 14, 806 (2014).

4.     T.-C Han et al, Sci Rep 3, 1593 (2013).

5.     T.-C Han et al,  Adv. Mat 26 , 1731 (2014).

6.     T.-C Han et al Phys Rev Lett 112, 054302, (2014).