Vibrations of amorphous Si are represented by the network model of Wooten, Winer, and Weaire and the forces of Stillinger and Weber. It is shown how the Kubo formula for thermal conductivity can be evaluated "exactly" assuming harmonic vibrations, making only finite-system-size errors. The results support a "shunt-resistor model" which fits data for glasses very well.

• Received 13 October 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.645