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 [1]. 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 [2] as well as at solid-liquid interfaces [3]. 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 [4], molecular functionalization [5,6], disorder [7], defects [8] and Phononic Crystals [9].
[1] Ramiere, A., Volz, S., & Amrit, J. (2016). Nature Materials, 1–12. http://doi.org/10.1038/nmat4574
[2] K. Saaskilahti, J. Oksanen, J. Tulkki, and S. Volz, Phys. Rev. B, 90, 134312, (2014).
[3] K. Saaskilahti, J. Oksanen, J. Tulkki, and S. Volz, Phys. Rev. E, 93, 52141 (2016).
[4] Shiyun Xiong, Kimmo Sääskilahti, Yuriy A. Kosevich, Haoxue Han, Davide Donadio, and Sebastian, Phys. Rev. Lett., 117, 025503 (2016).
[5] Haoxue Han, Yong Zhang, Nan Wang, Majid Kabiri Samani, Yuxiang Ni, Zainelabideen Y. Mijbil, Michael Edwards, Shiyun Xiong, Kimmo Sääskilahti, Murali Murugesan, Yifeng Fu, Lilei Ye, Hatef Sadeghi, Steven Bailey, Yuriy A. Kosevich, Colin J. Lambert, Johan Liu, & Sebastian Volz, Nature Communications, vol. 7, p. 1-9, 2016.
[6] Yong Zhang, Haoxue Han, Nan Wang, Pengtu Zhang, Yifeng Fu, Murali Murugesan, Michael Edwards, Kjell Jeppson, Sebastian Volz, and Johan Liu, Advanced Functional Materials, 24, 4430, (2015).
[7] Jeremie Maire, Roman Anufriev, Ryoto Yanagisawa, Aymeric Ramière and Sebastian Volz and Masahiro Nomura, submitted, https://arxiv.org/abs/1508.04574.
[8] Van-Truong Tran, Jérôme Saint-Martin, Philippe Dollfus and Sebastian Volz, submitted.
[9] Nomura, M., Nakagawa, J., Sawano, K., Maire, J., & Volz, S., Thermal conduction in Si and SiGe phononic crystals explained by phonon mean free path spectrum. Applied Physics Letters, 109(17), 173104–5, (2016).
报告人简介：
Prof Sebastian Volz obtained his Ph.D. in Mechanical Engineering in 1996 (Aeronautics « Grande Ecole» ENSMA) with a thesis on Nanoscale Thermal Physics. During 1997-1998, he was a postdoctoral research assistant at UCLA with Professor Gan Chen. He held tenured positions as Associate Professor in ENSMA, CNRS Research Fellow at Ecole Centrale Paris, CNRS full Professor at University of Tokyo and back at Ecole Centrale Paris. He is now becoming the Director of the LIMMS, the joint CNRS/U Tokyo Laboratory He has been carrying out research in solid state nanoscale thermal transport, including phonon-electron-photon modelling and metrologies for key applications such as thermoelectricity, photovoltaics and IC cooling. He is author of more than 150 papers and has edited three books. He has been leading the CNRS European Network ‘Thermal Nanosciences and Nanoengineering’ since 2001.
|
