Stiffness of interfacial bonding between two materials plays a major role in controlling the thermal conductance of the interface. We use nonequilibrium molecular dynamics simulations to study interfacial thermal conductance at an epitaxial interface between two fcc crystals with interatomic interactions described by Lennard Jones (LJ) potentials. The interface stiffness was varied by two different methods: (i) application of pressure and (ii) direct change of the interfacial bonding strength by varying the depth of potential well parameter of the LJ potential. Our results show that when the interfacial bonding strength is low, interfacial stiffness increases linearly with pressure due to the anharmonicity of atomic interactions. Consequently, the interfacial conductance increases, first proportionally to interfacial stiffness, and then it saturates at a high value. Quantitatively similar behavior is observed when the stiffness of the interfacial bonding is increased by directly varying the depth of the potential well parameter of the LJ potential. By contrast, when the interfacial bonding strength is high, thermal conductance is almost pressure independent and in fact slightly decreases with increasing pressure. This decrease can be explained by the change of overlap between the vibrational density of states (DOS) in the two crystalline materials.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Nov 8 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics