Abstract
The thermal conductivity of models of amorphous silicon and vitreous silica are discussed. In previous work on amorphous silicon, 216-and 1000-atom models were studied within the Kubo theory and the harmonic approximation using the Stillinger-Weber potential and good agreement with the experimental high-temperature apparent saturation value was obtained. In order to test the model dependence of such results we performed calculations for models based on the Keating potential. The Keating model apparently gives much less force-constant disorder than does the Stillinger-Weber model, as evident from the N dependence and the frequency range of localized states. We also present results of calculations for vitreous silica based on the Feuston-Garofalini model that we relaxed, using their potential, to zero pressure. The results for vitreous silica are in fair agreement with experiment at temperatures above 100K which corresponds to the lowest normal-mode frequency contained within the model.