headshot of Sangyeop Lee

Sangyeop Lee

Associate Professor
Mechanical Engineering & Materials Science


Since I joined Pitt in 2015, I have studied nanoscale thermal transport in solid materials. My research is currently focused on:
- Hydrodynamic phonon transport in graphitic materials
- Thermal transport in fully or partially disordered phase
- Application of machine learning techniques for thermal transport across different scales

My group uses Boltzmann transport theory, Green's function method, and molecular dynamics simulation, all of which use interatomic force constants calculated from density functional theory.

We currently have an opening for two Ph.D. students and a post-doc in the area of theory and simulation of phonon and electron transport. If you are interested in my research group, please send me your CV with research interests.


(2019) National Science Foundation CAREER award.

(2013) Poster award in Micro/Nano poster forum of ASME IMECE, San Diego, CA.

(2009 - 2014) Samsung scholarship ($50,000/year for tuition and stipend).

(2003) Graduated with honors (Magna Cum Laude) from KAIST.

(1999 - 2005) Korean government scholarship for B.S. and M.S. program (full tuition and boarding).

Ph.D. Mechanical Engineering, Massachusetts Institute of Technology, 2009 - 2015

M.S. Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology, 2003 - 2005

B.S. Mechanical and Aerospace Engineering, Korea Advanced Institute of Science and Technology, 1999 - 2003

Han, J., & Lee, S. (2024). Thermal resistance across Siā€“SiGe alloy interface from phonon distribution mismatch. Applied Physics Letters, 124(14).AIP Publishing. doi: 10.1063/5.0202880.

Li, X., Han, J., & Lee, S. (2023). Thermal resistance from non-equilibrium phonons at Si-Ge interface. MATERIALS TODAY PHYSICS, 34, 101063.Elsevier BV. doi: 10.1016/j.mtphys.2023.101063.

Lee, S., Chen, R., & Volz, S. (2022). Engineering and understanding of thermal conduction in materials. Journal of Applied Physics, 132(4).AIP Publishing. doi: 10.1063/5.0106187.

Li, X., Lee, H., Ou, E., Lee, S., & Shi, L. (2022). Reexamination of hydrodynamic phonon transport in thin graphite. JOURNAL OF APPLIED PHYSICS, 131(7).AIP Publishing. doi: 10.1063/5.0078772.

Gong, W., Garg, R., Guo, R., Lee, S., Cohen-Karni, T., & Shen, S. (2021). Thermal Transport in Multidimensional Silicon-Graphene Hybrid Nanostructures. ACS Appl Mater Interfaces, 13(42), 50206-50212.American Chemical Society (ACS). doi: 10.1021/acsami.1c08093.

Guo, R., Jiang, P., Tu, T., Lee, S., Sun, B., Peng, H., & Yang, R. (2021). Electrostatic interaction determines thermal conductivity anisotropy of Bi2O2Se. Cell Reports Physical Science, 2(11), 100624.Elsevier BV. doi: 10.1016/j.xcrp.2021.100624.

Jeong, J., Li, X., Lee, S., Shi, L., & Wang, Y. (2021). Transient Hydrodynamic Lattice Cooling by Picosecond Laser Irradiation of Graphite. PHYSICAL REVIEW LETTERS, 127(8), 085901.American Physical Society (APS). doi: 10.1103/PhysRevLett.127.085901.

Guo, R., & Lee, S. (2020). Mie scattering of phonons by point defects in IV-VI semiconductors PbTe and GeTe. MATERIALS TODAY PHYSICS, 12, 100177.Elsevier BV. doi: 10.1016/j.mtphys.2020.100177.

Hashemi, A., Babaei, H., & Lee, S. (2020). Effects of medium range order on propagon thermal conductivity in amorphous silicon. JOURNAL OF APPLIED PHYSICS, 127(4).AIP Publishing. doi: 10.1063/1.5124821.

Banaei, H., Guo, R., Hashemi, A., & Lee, S. (2019). Machine-learning-based interatomic potential for phonon transport in perfect crystalline Si and crystalline Si with vacancies. PHYSICAL REVIEW MATERIALS, 3(7).American Physical Society (APS). doi: 10.1103/PhysRevMaterials.3.074603.

Lee, S., & Li, X. (2019). (invited book chapter) Hydrodynamic Phonon Transport: Past, Present, and Prospect. In Nanoscale Energy Transport: Emerging Phenomena, Methods, and Applications, Liao, B. (Ed.). Institute of Physics Publishing, https://arxiv.org/pdf/1903.05731.pdf.

Lee, S., Li, X., & Guo, R. (2019). Thermal Resistance by Transition Between Collective and Non-Collective Phonon Flows in Graphitic Materials. NANOSCALE AND MICROSCALE THERMOPHYSICAL ENGINEERING, 23(3), 247-258.Informa UK Limited. doi: 10.1080/15567265.2019.1575497.

Li, X., & Lee, S. (2019). Crossover of ballistic, hydrodynamic, and diffusive phonon transport in suspended graphene. PHYSICAL REVIEW B, 99(8).American Physical Society (APS). doi: 10.1103/PhysRevB.99.085202.

Ou, E., Li, X., Lee, S., Watanabe, K., Taniguchi, T., & Shi, L. (2019). Four-Probe Measurement of Thermal Transport in Suspended Few-Layer Graphene With Polymer Residue. JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME, 141(6).ASME International. doi: 10.1115/1.4043167.

Li, X., & Lee, S. (2018). Role of hydrodynamic viscosity on phonon transport in suspended graphene. PHYSICAL REVIEW B, 97(9).American Physical Society (APS). doi: 10.1103/PhysRevB.97.094309.

Lindsay, L., Hua, C., Ruan, X.L., & Lee, S. (2018). Survey of ab initio phonon thermal transport. Materials Today Physics, 7, 106-120.Elsevier BV. doi: 10.1016/j.mtphys.2018.11.008.

Lee, S., & Lindsay, L. (2017). Hydrodynamic phonon drift and second sound in a (20,20) single-wall carbon nanotube. PHYSICAL REVIEW B, 95(18).American Physical Society (APS). doi: 10.1103/PhysRevB.95.184304.

Katz, H.E., & Poehler, T.O. (2016). Innovative Thermoelectric Materials. In Innovative Thermoelectric Materials: Polymer, Nanostructure and Composite Thermoelectrics, Katz, H., & Poehler, T. (Eds.). IMPERIAL COLLEGE PRESS. doi: 10.1142/p980.

Han, J., & Lee, S. Nonequilibrium thermal resistance of interfaces between III-V compounds. Physical Review Materials, 8(1).American Physical Society (APS). doi: 10.1103/physrevmaterials.8.014604.

Hashemi, A., Guo, R., Esfarjani, K., & Lee, S. Ab initio phonon transport across grain boundaries in graphene using machine learning based on small dataset. Physical Review Materials, 6(4).American Physical Society (APS). doi: 10.1103/physrevmaterials.6.044004.

Lee, D., Sayed, S.Y., Lee, S., Kuryak, C.A., Zhou, J., Chen, G., & Shao-Horn, Y. Quantitative analyses of enhanced thermoelectric properties of modulation-doped PEDOT:PSS/undoped Si (001) nanoscale heterostructures. Nanoscale, 8(47), 19754-19760.Royal Society of Chemistry (RSC). doi: 10.1039/c6nr06950a.

Lee, S., Broido, D., Esfarjani, K., & Chen, G. Hydrodynamic phonon transport in suspended graphene. Nature Communications, 6(1).Springer Science and Business Media LLC. doi: 10.1038/ncomms7290.

Lee, S., Esfarjani, K., Luo, T., Zhou, J., Tian, Z., & Chen, G. Resonant bonding leads to low lattice thermal conductivity. Nature Communications, 5(1).Springer Science and Business Media LLC. doi: 10.1038/ncomms4525.

Lee, S., Esfarjani, K., Mendoza, J., Dresselhaus, M.S., & Chen, G. Lattice thermal conductivity of Bi, Sb, and Bi-Sb alloy from first principles. Physical Review B, 89(8).American Physical Society (APS). doi: 10.1103/physrevb.89.085206.

Research interests

Solid-state energy conversion –...
Transport phenomena of heat, charge...