Theoretical insights into structural-electronic relationships and relative stability of the Cu-, Al- and O-terminated CuAlO2(0001) surfaces

Geometrical, electronic, energetic and thermodynamic properties of the Cu-, Al- and O-terminated CuAlO2(0001) surfaces have been studied by first-principles density functional theory (DFT) calculations. The atomic displacements and surface relaxations of four different terminations were taken into account. According to the results of the surface electronic properties, the Cu-terminated and Al-terminated CuAlO2(0001) surfaces are metallic, and the OI and OII surfaces present the p-type semiconductor surfaces. The surface energies and thermodynamic stability of CuAlO2(0001) surfaces have been analyzed, indicating that the OI surface is the thermodynamically most stable termination.