Casey N. Brock
Interdisciplinary Materials Science, Vanderbilt University, Nashville, TN 37235, USA
Matthew D. Gerboth
Interdisciplinary Materials Science, Vanderbilt University, Nashville, TN 37235, USA
Michael Fields
Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
D. Greg Walker
Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
The quality of results from a molecular dynamics (MD) simulation is determined by the accuracy of interatomic
forces. Often interatomic forces are determined using quantum mechanical methods such as density
functional theory (DFT). However, we have previously shown that DFT will not always produce accurate
forces. Presumably errors in the forces from DFT will cause errors in MD results, but the sensitivity has
not been quantified. In this work, we focus on how the thermal conductivity changes with respect to the interatomic
forces. Direct exploration of changes in thermal conductivity by varying parameters for the DFT
calculations (and thus the forces) would be very expensive, but we can extract this sensitivity indirectly using
classical MD with the Tersoff potential for diamond-cubic silicon. We have found that the percent change in
thermal conductivity of silicon is 0.56 times the percent change in average force magnitude, which provides
a useful metric for estimating errors in thermal conductivity resulting from errors in interatomic forces. We
expect the results to generalize to other materials and potentials.