Modeling LiNbO₃ Surfaces at Ambient Conditions

The adsorption of N 2, O 2, CO 2, CH 2, H 2, N 2 O, CO, and H 2 O on LiNbO 3 (0001) surfaces is simulated from first-principles in order to better understand its properties under ambient conditions. The adsorption energies and geometries, as well as the chemical bonding characteristics, are determined. Striking differences in the adsorption behavior at oppositely polarized surfaces are found. The effect of the adsorbed molecules on the surface charge is investigated. Phase diagrams for the adsorption of the different species dependent on pressure, temperature, and environment humidity are presented. They indicate that the desorption temperatures depend not only on the molecular species but also on the polarity of the surface.