Molecular dynamics study on temperature-dependent interfacial thermal resistance and wettability at Ga-Diamond/Cu interfaces

Thermal interface materials consisting of low-melting-point liquid metal indicate excellent thermal conductivity and good deformation capabilities, thereby displaying important role in thermal management applications under extreme conditions. This study introduces the molecular dynamics simulation to investigate the thermal transport and wetting behavior of Ga-Diamond and Ga-Cu solid-liquid interfaces. From 323 to 1023 K, the interfacial thermal resistance of both assemblies drops sharply as rising temperature boosts phonon coupling efficiency. Notably, analysis on the phonon participation ratio shows that Ga at the Ga-Cu interface indicates a high extended phonon share of 20%, which is larger than that at the Ga-Diamond system (16.1%). The interfacial phonon match illustrates dominant effect on the thermal transport difference. Moreover, the wettability analysis reveals that the contact angle θ of gallium at the two interfaces shows opposite tendency. The contact angle increases with temperature by 9.3% on the diamond surface, whereas it reduces by 79.6% on the Cu surface. In addition, a strong linear correlation between interfacial thermal resistance interfacial thermal resistance and cos θ is fitted, showing positive relation in the Ga-Diamond system and negative relation in the Ga-Cu system.