Keynote 8 Phononics: Manipulating Phonons with Electronic Analogues and Beyond
Date/Time Saturday, 4 May 2013 / 09:10 – 09:50
Venue Riverfront Ballroom

Prof. LI Baowen
Executive Director (NUS Graduate School for Integrative Sciences and Engineering)
National University of Singapore, Singapore

As the Executive Director of NGS, Professor Li endeavours to promote integrative research – Ph.D. research projects and coursework programmes that transcend traditional disciplinary boundaries. NGS has strong links with relevant Faculties, Schools and Research Centers of Excellence at NUS, and the various research institutes of the Agency for Science, Technology and Research (A*STAR), Singapores lead agency for research and development. NGS has also built synergistic, complementary partnerships with a select number of world-leading overseas research institutes and knowledge organisations in the USA, the UK, Continental Europe, Japan, Australia, and China.

In 1990, Professor Li received the Max-Planck Scholarship, and did his Ph. D thesis within two years, and got the Dr.rer.nat degree in 1992 from Universitat of Oldenburg. He joined NUS in July 2000 as an assistant professor, and promoted to associate professor with tenure in 2003 and full professor in 2007. He was Deputy Head of Physics Department, NUS from 2005-2006, founding executive director of Centre for Computational Science and Engineering, NUS since 2007.

An international leading expert in heat transport and co-founder of phononics, he has published more than 100 papers including 18 in Phys. Rev. Lett. He has delivered more than 100 keynote and invited talks. He has been awarded NUS Young Researcher Award in 2003, Temasek Young Investigator Award in 2004, National Science Award 2005, Singapore, and 2005 Overseas Chinese Physics Association (OCPA) Asia AchievementAward. 2007 IOP World Scientific Prize and Medal. 2008 Outstanding scientists of FOS. He is the coordinator of nonlinear and statistical physics at OCPA, and concurrent professor at Nanjing University, guest professor at Beijing Normal University, guest professor at Huazhong University of Science and Technology, advisory professor at East China Normal University.

His research interests include but not limited to phononics, heat conduction in low dimensional systems, thermoelectric effect in nanostructures, complex networks and systems biology, non-equilibrium statistical mechanics, inverse scattering problem, waves propagation and scattering in random/turbulent media etc.

The form of energy termed that typically derives from lattice vibrations, i.e. the phonons, is usually considered as waste energy and, moreover, deleterious to information processing.

However, in this talk, I will attempt to rebut this common view: By use of tailored models we demonstrate that phonons can be manipulated like electrons and photons can, thus enabling controlled heat transport. Moreover, we explain that phonons can be put to beneficial use to carry and process information.

In the first part, I will present ways to control phonon (heat) transport and how to process information for physical systems which are driven by a temperature bias. Particularly, I put forward the toolkit of familiar electronic analogues for exercising phononics; i.e. phononic devices which act as thermal diodes, thermal transistors, thermal logic gates and thermalmemories, etc.. These concepts are then put to work to transport, control and rectify heat in physical realistic nanosystems by devising practical designs of hybrid nanostructures that permit the operation of functional phononic devices and, as well, report first experimental realizations.

Next, I discuss yet richer possibilities to manipulate heat flow by use of time varying thermal bath temperatures or various other external fields. These give rise to a plenty of intriguing phononic nonequilibrium phenomena as for example the directed shuttling of heat, a geometrical phase induced heat pumping, or the phonon Hall effect, that all may find its way into operation with electronic analogues.

Last, the generalization of these concepts to control elastic vibrations and acoustic waves will be presented.