On the upper limit of thermal conductivity GaN crystals
The maximal value of thermal conductivity κ_{max} of the perfect wurzite GaN crystal containing isotopes of natural abundance is estimated. Our upper limit of κ=4800 W/Km at T_{max}=32 K is smaller than calculated by Liu and Balandin κ=6000 W/Km and higher than obtained by Slack et al κ=3750 W/Km. The phenomenological dependence κ\propto T^{-1.43} obtained by Mion et al for the temperature interval 300-450 K is extended to 200-300K. For temperatures higher than T_max the best fitting of our experimental data to Callaway's formula is obtained for Grueneisen's constant equal to γ= 1.35.
cond-mat.mtrl-sci↗