Thermal resistance of an interfacial molecular layer by first-principles molecular dynamics

Thuy-Quynh Duong , Carlo Massobrio , Guido Ori , Mauro Boero , Évelyne Martin (1, 2)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 PHYSIQUE - IEMN - Physique - IEMN

The approach-to-equilibrium molecular dynamics (AEMD) methodology is applied in combination with first-principles molecular dynamics (FPMD) to investigate the thermal transfer between two silicon blocks connected by a molecular layer. Our configuration consists of alkanes molecules strongly coupled to the silicon surfaces via covalent bonds. In the phase 1 of AEMD, the two Si blocks are thermalized at high and low temperatures to form the hot and cold reservoirs. During the phase 2 of AEMD, a transfer between reservoirs occurs until thermal equilibrium is reached. The transfer across the interface dominates the transient over heat conduction within the reservoirs. The value of the thermal interface conductance is in agreement with experimental data obtained for analogous bonding cases between molecules and reservoirs. The dependence on length of the thermal interface resistance features two contributions. One is constant (the resistance at the silicon/molecule interface) while the other varies linearly with the length of the molecular chains (diffusive transport). The corresponding value of the thermal conductivity agrees well with experiments.

Domaines: Matière Condensée [cond-mat]

Thuy-Quynh Duong, Carlo Massobrio, Guido Ori, Mauro Boero, Évelyne Martin. Thermal resistance of an interfacial molecular layer by first-principles molecular dynamics. Journal of Chemical Physics, 2020, 153 (7), pp.074704. ⟨10.1063/5.0014232⟩. ⟨hal-02990565⟩