Аннотация:Abstract—The molecular dynamics (MD) method seems to be the most promising method for determining
the lattice contribution to the overall thermal conductivity of metals and metal alloys. In this study, the
MD method with a proven potential is used for studying the lattice thermal conductivity of aluminum at high
and low temperatures. It is shown that standard algorithms are more convenient for calculating the lattice
thermal conductivity coefficient at high temperatures. In this case, the thermal conductivity coefficient is cal-
culated using the Fourier equation, and the MD calculations are used to simulate a steady nonequilibrium
state with a linear temperature gradient at a length comparable to the size of the calculated cell. This approach
gives the values of the lattice thermal conductivity coefficient, which are in good agreement with the results
of the first principles calculations. The thermal conductivity coefficient decreases with a decrease in the size
of the base crystallite because of the depletion of the low frequency section of the phonon spectrum, the con-
tribution of which to thermal conductivity becomes insignificant with an increase in the temperature. At high
temperatures, the thermal conductivity coefficient does not depend on the crystallite size and agrees with the
value obtained from the first principles calculations. To calculate the thermal conductivity at low tempera-
tures, a new method based on the homogeneous heat equation for an infinite line is proposed. In this case,
the MD method is used to obtain a steady state nonequilibrium temperature distribution in the system in the
form of a Gaussian curve that corresponds to the fundamental solution of the equation. The approximation
of system relaxation from the nonequilibrium state to the equilibrium one makes it possible to determine the
thermal diffusivity coefficient related to the thermal conductivity coefficient. The test calculations performed
for a thin aluminum film at low temperatures with different initial conditions show that the obtained thermal
diffusivity coefficient does not depend on the parameters of the initial Gaussian distribution, which suggests
the applicability of the proposed method for studying the lattice thermal conductivity.