Exploring the low-index surfaces of D52-La2O3 from the first-principles calculations

The surface relaxations, surface stability, electronic structures, and equilibrium morphology of D5₂-La₂O₃ were analyzed by means of first-principles calculations. The stoichiometric surfaces of D5₂-La₂O₃ possess thermodynamic energies of the following order: (0 0 1) < (1 1 0) < (1 0 0). Changes in temperature and the partial pressure of oxygen were employed to determine the energy of the non-stoichiometric surfaces. The results indicated that the energies of the (ns-1La1O)-terminated (1 0 0) and (ns-1La)-terminated (0 0 1) surfaces increased with increasing oxygen partial pressures and decreased with temperatures, whereas the (ns-1O)-terminated (0 0 1) and (ns-1O)-terminated (1 0 0) surfaces exhibited the reverse rule. According to the calculated density of states, surface relaxations primarily impact the surface electronic structures. The Gibbs-Wulff model was used to forecast the equilibrium morphology of D5₂-La₂O₃, which followed in comparison with other’s experimental findings.