Assessing the applicability of quantum corrections to classical thermal conductivity predictions

The validity of the commonly used quantum corrections for mapping a classically predicted thermal conductivity onto a corresponding quantum value are assessed by self-consistently predicting the classical and quantum thermal conductivities of a crystalline silicon system via lattice-dynamics calculations. Applying the quantum corrections to the classical predictions, with or without the zero-point energy, does not bring them into better agreement with the quantum predictions compared to the uncorrected classical values above temperatures of 200 K. By examining the mode dependence of the phonon properties, we demonstrate that thermal conductivity cannot be quantum corrected on a system level. We explore the source of the differences in the quantum and classical phonon relaxation times on a mode-by-mode basis.