Universal interfacial thermal resistance at high frequencies

The existence of a universal interfacial thermal resistance in a broad range of systems is shown using linear response theory and computations of realistic materials. When the thermal excitation is modulated up to frequencies larger than the intrinsic resistance scattering rate defined in a previous paper [A. Rajabpour and S. Volz, J. Appl. Phys. 108, 094324 (2010)], the interfacial resistance becomes reversely proportional to frequency and only depends on the number of degrees of freedom involved in the heat transfer between both systems. We present molecular dynamics simulations of connected crystals corroborating these statements from both quantitative and qualitative viewpoints. This finding significantly impacts the thermal management of nanoelectronic systems at nanoscales where heat removal mainly relies on interfacial scattering.

Figure 1

(a) Schematic of the LJ systems including LJ1 (small spheres) and LJ2 (large spheres); (b) schematic of the solid interface and the potential cutoff layers defining the areas where temperatures $T_1$ and $T_2$ are computed. $N_1$ and $N_2$ correspond to the number of degrees of freedom involved in the temperature computations.

Figure 2

Thermal resistance vs frequency calculated with MD (colored lines) and the model from Eq. (3) (black line) for LJ crystals. Results are reported for different mass ratios (a), different interacting potential depths (b), and different equilibrium temperatures (c) for LJ crystals.

Figure 3

Temperature difference correlation function calculated with MD for $m_2/m_1$ = 4 (colored line) for LJ crystals and the fitting using an exponentially decaying function (black line).

Figure 4

Thermal resistance vs frequency calculated with MD (colored lines) and the model from Eq. (6) (black line) calculates for Si crystals.