Synchrotron radiation effect on the AlN thermal conductivity

The effect of synchrotron radiation on the thermal conductivity of an AlN single crystal was studied in the temperature range from 5 to 410 K. It was found that in the intermediate temperatures region (20–70 K) the thermal conductivity of irradiated sample decreases by 11%, while in the region of high temperatures above 150 K the effect is negligible. Within the framework of the first-principles approach, the temperature dependence of the thermal conductivity of an AlN crystal with a wurtzite-type structure was calculated. The calculation results are in a satisfactory agreement with the experimental data at temperatures above 200 K. It is shown that the reason for such a change in the thermal conductivity and the nature of its temperature dependence may be the interaction of thermal phonons with the charge carriers bound to alloying defects in the crystal lattice (primarily with oxygen atoms and aluminum vacancies impurity complexes).