Lattice thermal conductivity: A comparison of molecular dynamics and anharmonic lattice dynamics
The thermal conductivity of a monatomic face-centered-cubic lattice has been calculated over a range of temperatures from one-twentieth to one-half the melting temperature. An inverse-twelfth-power ''soft-sphere'' potential was used to represent the interatomic forces. We have examined, quantitatively, the approximations involved in deriving the Peierls phonon-transport expression for the thermal conductivity and have determined the temperature range over which it is useful. This has involved extensive comparisons with the formally exact Green-Kubo method, using molecular dynamics to generate the phase-space trajectories. At low temperatures, the relaxation processes in a crystal can be described in terms of phonon lifetimes. We have calculated the lifetimes of all the phonon states of 108-, 256-, and 864-particle classical crystals, with periodic boundaries, by molecular dynamics and by anharmonic perturbation theory. These lifetimes were then used to estimate the thermal conductivity.
- Research Organization:
- Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Livermore, California 94550
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5170597
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 34:8
- Country of Publication:
- United States
- Language:
- English
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