Density functional theory study of 3R-and 2H-CuAlO2 under pressure

We present a first-principles density-functional theory based study of the impact of pressure on the structural and elastic properties of bulk 3R- and 2H-CuAlO2. The ground state properties of 3R- and 2H-CuAlO2 are obtained, which are in good agreement with previous experimental and theoretical data. The analysis of enthalpy variation with pressure indicates the phase transition pressure between 3R and 2H is 15.4 GPa. The independent elastic constants of 3R- and 2H-CuAlO2 are calculated. As the applied pressure increases, the calculations show the presences of mechanical instability at 26.2 and 27.8 GPa for 3R-and 2H-CuAlO2, which are possibly related with the phase transitions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3499659]