Effect of lattice relaxation on thermal conductivity of fcc-based structures: an efficient procedure of molecular dynamics simulation

MY Ha and G Choi and DH Kim and HS Kim and SH Park and WB Lee, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 25, 055011 (2017).

DOI: 10.1088/1361-651X/aa6a2d

This work studied the computational details of the Green-Kubo method with molecular dynamics (MD) simulation for thermal conductivity prediction. In MD thermal conductivity calculation, little consensus has been made about the inclusion of zero-pressure volume relaxation in the isobaric-isothermal (NpT) ensemble, which determines the simulation lattice parameters. Simulations of fcc-based structures with different lattice parameters were performed to calculate lattice thermal conductivities and phonon density of states, and the results were compared to experimental reports and ab initio results to conclude that NpT volume relaxation is crucial for accurate prediction of thermal conductivity. In addition, the relation between thermal conductivity and interatomic potential cutoff distance was also analysed in the context of lattice relaxation. The results suggested that calculated thermal conductivity is strictly dependent on the lattice parameter and essentially independent of the cutoff distance. It was also shown that reducing the cutoff distance can greatly accelerate the thermal conductivity calculation, even without sacrificing the accuracy of thermal conductivity.

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