Thermal Conductivity in Nanoscale Lennard-Jones Systems: Size Effects in the Fluid and Solid Phases

Abstract

We simulate fluid and solid Lennard-Jones argon systems via non-equilibrium molecular dynamics and study how the system behaves under an imposed temperature gradient until it reaches the stationary state, from where the thermal conductivity is calculated. We show that transient pressure waves propagate in the system giving rise to a density oscillation pattern. Based on the damping of this pattern we estimate the time needed to reach the stationary state. We also show that thermal conductivity is size independent in the fluid phase, while it increases until the Casimir limit in the solid phase.