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| Title |  Thermal transport simulation from first principles and machine learning 

| Speaker | Prof. Sangyeop Lee, Department of Mechanical Engineering and Materials Science, Department of Physics and Astronomy (courtesy appointment) University of Pittsburgh   

* BIOGRAPHY 

Dr. Sangyeop Lee received B.S. and M.S. degrees from KAIST in 2003 and 2005. After working at the fuel cell research center of KIST for four years, he started his Ph.D. study at Massachusetts Institute of Technology, focusing on the study of phonon and electron transport using first principles calculation and experimental characterization. He received a Ph.D. degree from MIT in 2015 and then joined the University of Pittsburgh. His research interests are transport phenomena of energy, currently focusing on the thermal transport in disordered media using first principles, machine learning, and the Boltzmann transport theory. He received a National Science Foundation Career award in 2019 and the Samsung Scholarship for his Ph.D. study 

| Date | 2023년 4월 7일(금) 

| Time | 오전 11시 ~ 

| Venue | 온라인 줌 https://snu-ac-kr.zoom.us/j/97604374061?pwd=eVpVUFNPNEh6dzIyTWkvWHlmejQzZz09

                회의 ID: 976 0437 4061 

                암호: 1010

| Abstract |

Thermal transport in solids plays a critical role in many engineering applications, including energy conversion/storage, information technologies, manufacturing, etc. Atomistic simulations have been critical in understanding the thermal transport properties of condensed matter. Recent studies based on first-principles calculations have demonstrated their predictive power without requiring adjustable parameters, leading to the discovery of new materials with exotic thermal transport properties. However, these successes have been limited to perfect crystals due to the computational expense involved. Imperfect materials with many defects are more relevant to real-world engineering applications, but their physical mechanisms remain poorly understood. In this seminar, I will discuss several recent studies conducted by my research group on thermal transport in disordered solids using atomistic simulations. Our efforts focus on extending the first-principles method, established for bulk single crystal materials, to materials with defects and interfaces to better understand thermal transport in imperfect materials. The topics I will cover include: (i) Mie scattering of phonons by a point defect, which breaks the long-standing Rayleigh scattering picture that has been around for several decades; (ii) the use of machine learning techniques to simulate phonon-defect scattering with first-principles accuracy, which is prohibitively expensive when direct first-principles methods are used; and (iii) the significant non-equilibrium phonons near a heterostructure interface, highlighting their substantial contribution to the overall interfacial thermal resistance 

| Host |  장혜진 교수 (02-880-7096)