Effects of bulk and interfacial anharmonicity on thermal conductance at solid/solid interfaces

Article
Authors:Le, Nam Q., Department of Mechanical and Aerospace EngineeringUniversity of Virginia Polanco, Carlos A., Department of Electrical and Computer EngineeringUniversity of Virginia Rastgarkafshgarkolaei, Rouzbeh , Department of Mechanical and Aerospace EngineeringUniversity of Virginia Zhang, Jinjie, Department of Electrical and Computer EngineeringUniversity of Virginia Ghosh, Avik, Department of Electrical and Computer Engineering University of Virginia Norris, Pamela M. , Department of Mechanical and Aerospace Engineering University of Virginia
Abstract:

We present the results of classical molecular dynamics simulations to assess the relative contributions to interfacial thermal conductance from inelastic phonon processes at the interface and in the adjacent bulk materials. The simulated system is the prototypical interface between argon and “heavy argon” crystals, which enables comparison with many past computational studies. We run simulations interchanging the Lennard-Jones potential with its harmonic approximation to test the effect of anharmonicity on conductance. The results confirm that the presence of anharmonicity is correlated with increasing thermal conductance with temperature, which supports conclusions from prior experimental and theoretical work. However, in the model Ar/heavy-Ar system, anharmonic effects at the interface itself contribute a surprisingly small part of the total thermal conductance. The larger fraction of the thermal conductance at high temperatures arises from anharmonic effects away from the interface. These observations are supported by comparisons of the spectral energy density, which suggest that bulk anharmonic processes increase the interfacial conductance by thermalizing energy from modes with low transmission to modes with high transmission.

Rights:
All rights reserved (no additional license for public reuse)
Language:
English
Source Citation:

Le, Nam Q., Carlos A. Polanco, Rouzbeh Rastgarkafshgarkolaei, Jingjie Zhang, Avik W. Ghosh, and Pamela M. Norris. “Effects of bulk and interfacial anharmonicity on thermal conductance at solid/solid interfaces.” Physical Review B 95.24, (2017): 245417-1-245417-8. Available: https://doi.org/10.1103/PhysRevB.95.245417

Publisher:
American Physical Society
Published Date:
June 16, 2017