Session: 11-60-01: Simulations of Thermal Transport in Nanostructures and across Interfaces

Paper Number: 119812

119812 - Interfacial Thermal Conductance Spectrum in Nonequilibrium Molecular Dynamics Simulations Considering Anharmonicity, Asymmetry and Quantum Effects 

Interfacial thermal transport is critical for many thermal-related applications, such as heat dissipation in electronics. While the total interfacial thermal conductance (ITC) can be easily measured or calculated, the ITC spectral mapping has been investigated only recently and is not fully understood. The ITC spectrum has been widely investigated, mainly through empirical models [1,2] and atomistic Green's function (AGF) method [3–5], and permutations thereof that only consider the elastic scatterings after Kapitza firstly defined the interfacial heat transfer between two different materials in 1941 [6]. Only recently, the anharmonic phonon scatterings are introduced into the analysis of the ITC spectrum. For instance, Guo et al. [7,8], and Dai and Tian [9] have included the three-phonon scatterings in their AGF-calculated ITC spectrum. Although tremendous progress in quantifying the ITC spectrum at interfaces has been achieved, a systematic investigation of the influence of anharmonicity, asymmetry, and quantum effects on the ITC spectrum is still lacking.

By combining nonequilibrium molecular dynamics simulations and atomistic Green's function method, we systematically investigate the ITC spectrum across an ideal interface, i.e., the argon/heavy argon interface. Here, we investigate the influence of anharmonicity, asymmetry, and quantum effects on the ITC spectrum at the planar interfaces of LJ solids, i.e., argon/heavy argon interfaces, using the spectral heat current method in the frame of nonequilibrium molecular dynamics simulations and atomistic Green's function. The ITC is found to increase gradually with temperature as more phonons and anharmonic scattering channels are activated, e.g., the vibrations with frequencies larger than 1 THz can contribute only 5% at 2 K while 15% at 40 K to the total ITC. Meanwhile, while the thermal conductance resulting from the left interfacial Hamiltonian is identical to that contributed by the right interfacial Hamiltonian, the corresponding ITC spectrums resulting from the left and right Hamiltonians are quite different due to the asymmetry anharmonic interfacial phonon scatterings caused by the dissimilar vibrational property of the two interfacial contacts. The quantum effect is further found to be important for the ITC spectrum at low temperatures, e.g., below 30 K in our systems. Our results here provide a fundamental understanding of the ITC in molecular dynamics and suggest a strategy to calculate the interfacial thermal conductance in all temperature ranges using molecular dynamics.

Reference

[1]        W. A. Little, Can. J. Phys. 37, 334 (1959).

[2]        E. T. Swartz and R. O. Pohl, Rev. Mod. Phys. 61, 605 (1989).

[3]        W. Zhang, T. S. Fisher, and N. Mingo, J. Heat Transfer 129, 483 (2007).

[4]        W. Zhang, T. S. Fisher, and N. Mingo, Numerical Heat Transfer, Part B: Fundamentals 51, 333 (2007).

[5]        J.-S. Wang, J. Wang, and J. T. Lü, Eur. Phys. J. B 62, 381 (2008).

[6]        P. L. Kapitza, Phys. Rev. 60, 354 (1941).

[7]        Y. Guo et al., Phys. Rev. B 102, 195412 (2020).

[8]        Y. Guo et al., Phys. Rev. B 103, 174306 (2021).

[9]        J. Dai and Z. Tian, Phys. Rev. B 101, 041301 (2020).

Presenting Author: Yixin Xu Hong Kong University of Science and Technology

Presenting Author Biography: Mr. Yixin Xu is now a Ph.D. Candidate at Hong Kong University of Science and Technology, majoring in mechanical engineering. His research interests focus on nanoscale thermal transport, including phonon transport across solid/solid interface and phase-change heat transfer, e.g., boiling and condensation. Mr. Xu is now investigating the thermal transport of complex systems with multi-heterostructures to advance the understanding and optimization of thermal transport within these systems.

Authors:

Yixin Xu Hong Kong University of Science and Technology
Lina Yang Beijing Institute of Technology
Yanguang Zhou Hong Kong University of Science and Technology