Insight into lattice thermal impedance via equilibrium molecular dynamics: case study on Al

Abstract

Using results of equilibrium molecular dynamics simulation in conjunction with the Green–Kubo formalism, we present a general treatment of thermal impedance of a crystal lattice with a monatomic unit cell. The treatment is based on an analytical expression for the heat current autocorrelation function which reveals, in a monatomic lattice, an energy gap between the origin of the phonon states and the beginning of the energy spectrum of the so-called acoustic short-range phonon modes. Although, we consider here the f.c.c. Al model as a case example, the analytical expression is shown to be consistent for different models of elemental f.c.c. crystals over a wide temperature range. Furthermore, we predict a frequency ‘window’ where the thermal waves can be generated in a monatomic lattice by an external periodic temperature perturbation.

Keywords:

• Thermal transport
• thermal conductivity
• phonons
• molecular dynamics
• Green–Kubo formalism
• aluminium

Funding

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

Additional information

Funding

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