The thermal conductivity of hexagonal boron nitride parallel to the basal planes

Detailed measurements of the basal thermal conductivity and specific heat of boron nitride have recently been reported over the range 1.5–350 K. Boron nitride is a lattice conductor with a conductivity varying as T^2.4 below 10 K, while the lattice specific heat varies as T³ over the same range. This anomalous difference in the temperature dependence of lattice conductivity and specific heat is similar to that observed in graphite. The theory of the lattice conductivity of graphite parallel to the basal planes is applied to the explanation of this anomaly. It appears that the value of C₄₄ in this lattice must be smaller than that of graphite.