Molecular dynamics prediction of phonon-mediated thermal conductivity of f.c.c. Cu

Abstract

The phonon-mediated thermal conductivity of f.c.c. Cu is investigated in detail in the temperature range 40–1300 K. The calculations are performed in the framework of equilibrium molecular dynamics making use of the Green–Kubo formalism and one of the most reliable embedded-atom method potentials for Cu. It is found that the temporal decay of the heat current autocorrelation function (HCACF) of the Cu model at low and intermediate temperatures demonstrate a more complex behaviour than the two-stage decay observed previously for the f.c.c. Ar model. After the first stage of decay, it demonstrates a peak in the temperature range 40–800 K. A decomposition model of the HCACF is introduced. In the framework of that model we demonstrate that a classical description of the phonon thermal transport in the Cu model can be used down to around one quarter of the Debye temperature (about 90 K). Also, we find that above 300 K the thermal conductivity of the Cu model varies with temperature more rapidly than , following an exponent close to −1.4 in agreement with previous calculations on the Ar model. Phonon thermal conductivity of Cu is found to be about one order of magnitude higher than Ar. The phonon contribution to the total thermal conductivity of Cu can be estimated to be about 0.5% at 1300 K and about 10% at 90 K.

Keywords:

• thermal transport
• thermal conductivity
• phonons
• molecular dynamics
• Green–Kubo equation
• copper

Acknowledgements

This research was supported by the Australian Research Council through its Discovery Project Grants Scheme.