Spectral mapping of heat transfer mechanisms at liquid-solid interfaces

• Published in: Physical review. E Vol. 93; no. 5; p. 052141
• Main Authors: Sääskilahti, K, Oksanen, J, Tulkki, J, Volz, S
• Format: Journal Article
• Language: English
• Published: United States 24.05.2016
• ISSN: 2470-0053
• DOI: 10.1103/physreve.93.052141

Thermal transport through liquid-solid interfaces plays an important role in many chemical and biological processes, and better understanding of liquid-solid energy transfer is expected to enable improving the efficiency of thermally driven applications. We determine the spectral distribution of thermal current at liquid-solid interfaces from nonequilibrium molecular dynamics, delivering a detailed picture of the contributions of different vibrational modes to liquid-solid energy transfer. Our results show that surface modes located at the Brillouin zone edge and polarized along the liquid-solid surface normal play a crucial role in liquid-solid energy transfer. Strong liquid-solid adhesion allows also for the coupling of in-plane polarized modes in the solid with the liquid, enhancing the heat-transfer rate and enabling efficient energy transfer up to the cutoff frequency of the solid. Our results provide fundamental understanding of the energy-transfer mechanisms in liquid-solid systems and enable detailed investigations of energy transfer between, e.g., water and organic molecules.