【创源大讲堂】Sebastian Volz教授 How Phonon Spectrum Exposes Thermal Behaviors: From Kapitza Resistance to Phonon Capacitors

讲座时间:5月28日（周一）10：00-11：00

讲座地点：X5527

主讲人:  Sebastian Volz 教授

简介：Sebastian Volz 教授

Dr. Sebastian Volz is a Full Professor at the French National scientific research center (CNRS), Ecole Centrale Paris (France) and University of Tokyo (Japan). He received his Ph.D degree in engineering physics from University of Poitiers (France) in 1993. He was then appointed post-doctoral fellow at the University of Caliornia, Los Angeles (USA) with Prof. Gang Chen. So far, He has published 3 books, 11 book chapters and over 140 scientific articles, including Nature Materials, Nature Photonics, Nature Communications, PRL, and Adv Mater. Currently, he is the Associate Editor of the journal of Nanoscale and Microscale Thermophysical Engineering and the journal of Nanoelecronics and Optoelectronics.

讲座题目：Thermal conductivity engineering in nanostructures

讲座语言：英文

内容简介：With the recent advancement of experimental and numerical methods, the complex modal content of the phonon heat flux has been progressively uncovered in bulk materials but also in nanostructures and molecular systems. Key quantities such as the mode relaxation time or mean free path, which had been known only for simplified mode dispersions, were finally extracted. And while state-of-the-art descriptions based on differential transport equations would mainly rely on bulk properties, the impact of atomic scale mechanisms on heat conduction has been revealed. As a first step, the predominant role of the spectral content of phonon heat flux at interfaces is firstly emphasized by experimental investigations revealing frequency selection mechanisms. This behaviour was envisioned by Adamenko and Fuks several decades ago to explain Kapitza resistance and we will show the experimental validation of their theory.

A new theoretical path is then proposed to unravel the spectral content of phonon interfacial conductance based on Molecular Dynamics simulations. This method directly provides mode-to-mode phonon transmission, including anharmonic contributions in solid-solid as well as at solid-liquid interfaces. We will show that this method can also be extended to provide the spectral mean free path in systems with translation symmetry. Further illustrations will finally be provided to show how the spectral phonon distribution can be analyzed and controlled via resonator structures, molecular functionalization, disorder, defects and Phononic Crystals.