How does the accuracy of interatomic force constants affect the prediction of lattice thermal conductivity

TL;DR

This study examines how the precision of interatomic force constants influences the accuracy of lattice thermal conductivity predictions in two-dimensional materials, revealing that common accuracy criteria may be insufficient.

Contribution

It demonstrates that typical force errors significantly impact thermal conductivity predictions and questions the reliability of translational invariance and Grüneisen parameters as accuracy indicators.

Findings

Force inaccuracies cause large deviations in thermal conductivity predictions.

Imposing translational invariance does not always improve results.

Grüneisen parameters are not reliable criteria for IFC accuracy.

Abstract

Solving Peierls-Boltzmann transport equation with interatomic force constants (IFCs) from first-principles calculations has been a widely used method for predicting lattice thermal conductivity of three-dimensional materials. With the increasing research interests in two-dimensional materials, this method is directly applied to them but different works show quite different results. In this work, classical potential was used to investigate the effect of the accuracy of IFCs on the predicted thermal conductivity. Inaccuracies were introduced to the third-order IFCs by generating errors in the input forces. When the force error lies in the typical value from first-principles calculations, the calculated thermal conductivity would be quite different from the benchmark value. It is found that imposing translational invariance conditions cannot always guarantee a better thermal conductivity result. It is also shown that Gr\"uneisen parameters cannot be used as a necessary and sufficient criterion for the accuracy of third-order IFCs in the aspect of predicting thermal conductivity.