Thermal Interface Conductance between Aluminum and Silicon by Molecular Dynamics Simulations

The thermal interface conductance between Al and Si was simulated by a non-equilibrium molecular dynamics method. In the simulations, the coupling between electrons and phonons in Al are considered by using a stochastic force. The results show the size dependence of the interface thermal conductance and the effect of electron-phonon coupling on the interface thermal conductance. To understand the mechanism of interface resistance, the vibration power spectra are calculated. We find that the atomic level disorder near the interface is an important aspect of interfacial phonon transport, which leads to a modification of the phonon states near the interface. There, the vibrational spectrum near the interface greatly differs from the bulk. This change in the vibrational spectrum affects the results predicted by AMM and DMM theories and indicates new physics is involved with phonon transport across interfaces. Keywords:Comment: Journal of Computational and Theoretical Nanoscience 201

Effect of Electron-Phonon Coupling on Thermal Transport across Metal-Nonmetal Interface - A Second Look

The effect of electron-phonon (e-ph) coupling on thermal transport across metal-nonmetal interfaces is yet to be completely understood. In this paper, we use a series of molecular dynamics (MD) simulations with e-ph coupling effect included by Langevin dynamics to calculate the thermal conductance at a model metal-nonmetal interface. It is found that while e-ph coupling can present additional thermal resistance on top of the phonon-phonon thermal resistance, it can also make the phonon-phonon thermal conductance larger than the pure phonon transport case. This is because the e-ph interaction can disturb the phonon subsystem and enhance the energy communication between different phonon modes inside the metal. This facilitates redistributing phonon energy into modes that can more easily transfer energy across the interfaces. Compared to the pure phonon thermal conduction, the total thermal conductance with e-ph coupling effect can become either smaller or larger depending on the coupling factor. This result helps clarify the role of e-ph coupling in thermal transport across metal-nonmetal interface

A method to predict the thermal conductance of a bolted joint

Analytical method to predict interface thermal conductance of bolted joint

Heat transport in proximity structures

We study heat and charge transport through a normal diffusive wire coupled with a superconducting wire over the region smaller than the coherence length. Due to partial Andreev reflection of quasiparticles from the interface, the subgap thermal flow is essentially suppressed and approaches zero along with energy, which is specific for diffusive structures. Whereas the electric conductance shows conventional reentrance effect, the thermal conductance rapidly decreases with temperature which qualitatively explains the results of recent experiments. In the Andreev interferometer geometry, the thermal conductance experiences full-scale oscillations with the order parameter phase difference.Comment: 4 pages, 4 figures, minor revision, to be published in Phys. Rev. Let

Influence of the electron-phonon interfacial conductance on the thermal transport at metal/dielectric interfaces

Thermal boundary conductance at a metal-dieletric interface is a quantity of prime importance for heat management at the nanoscale. While the boundary conductance is usually ascribed to the coupling between metal phonons and dielectric phonons, in this work we examine the influence of a direct coupling between the metal electrons and the dielectric phonons. The effect of electron- phonon processes is generally believed to be resistive, and tends to decrease the overall thermal boundary conductance as compared to the phonon-phonon conductance {\sigma}p . Here, we find that the effect of a direct coupling {\sigma}e is to enhance the effective thermal conductance, between the metal and the dielectric. Resistive effects turn out to be important only for thin films of metals having a low electron-phonon coupling strength. Two approaches are explored to reach these conclusions. First, we present an analytical solution of the two-temperature model to compute the effective conductance which account for all the relevant energy channels, as a function of {\sigma}e , {\sigma}p and the electron-phonon coupling factor G. Second, we use numerical resolution to examine the influence of {\sigma}e on two realistic cases: gold film on silicon or silica substrates. We point out the implications for the interpretation of time-resolved thermoreflectance experiments