Published online by Cambridge University Press: 25 February 2011
The thermal conductivity of boron carbides at high temperatures presents a fundamental challenge to theory. One of the striking features is that, while in B4C it displays “normal” behaviour in that it decreases with increasing temperature, in B9C it is nearly temperature-independent. We address this feature through a model calculation which assumes the heat current to be due to carrier phonons whose frequency is modulated by lower-frequency phonons which “dress” the carrier phonons through strong interaction. Preliminary calculations show satisfactory but partial agreement with experiment for reasonable parameters and delineate areas for further investigation of the vibrational properties of boron carbides.