Structural and thermodynamic properties of GaN at high pressures and high temperatures

The structural and thermodynamic properties of GaN have been investigated systematically using the molecular dynamics method with Buckingham potential. These properties including phase transition, lattice constant, thermal expansion, isothermal bulk modulus, and specific heat were calculated in a wide range of temperatures (300-3000 K) and pressures (0-65 GPa). The obtained structural and thermodynamic parameters under normal state are found to be in good agreement with the existing experimental data and theoretical results. Meanwhile, some thermodynamic parameters have been predicted at elevated temperatures and high pressures based on the reliable potential model. These detailed knowledge of thermodynamic behavior at extreme P-T conditions are of fundamental importance to our understanding of the structural properties of GaN.