Hydrostatic pressure effect on lattice thermal conductivity of wurtzite GaN semiconductor

Debye–Callaway model in combination with the Murnaghan and Clapeyron equations was used to calculate the hydrostatic pressure effects on lattice thermal conductivity (LTC) of wurtzite gallium nitride. The calculations are for the longitudinal and transverse phonon modes. The results are efficiently fitted with the whole temperature (1–400) of the experimental data. The peak value of LTC declines with the applied pressure from 0 to 14 GPa. This result is due to the decreasing Debye temperature, group velocity and lattice volume. Furthermore, pressure affected the number of dislocations, sample size and Gruneisen parameter (longitudinal and transverse) modes. Consequently, the values of above parameters at zero GPa are \(2.5\times {10}^{13 }{{\text{m}}}^{-2}, 1.8 {\text{mm}}\) $2.5\times {10}^{13}{\text{m}}^{-2},1.8\text{mm}$ , \(0.93 \,{\text{and}}\, 0.52\) $0.93\text{and}0.52$ , whilst the values at 14 GPa are \(15\times {10}^{15}{\mathrm{ m}}^{-2}, 1.68 {\text{mm}},\) $15\times {10}^{15}{\mathrm{m}}^{-2},1.68\text{mm},$ \(0.818 \,{\text{and}}\, 0.469\) $0.818\text{and}0.469$ , respectively. The results show that hydrostatic pressure does not affect the number of impurities and electron concentrations.