First-principles analysis on proton diffusivity in La3NbO7

We have theoretically investigated proton sites and migration paths in La3NbO7 from first principles. Protons prefer the non-shared oxide ions to the isolated and the corner-shared oxide ions, which mainly results from repulsive electrostatic interactions with La3 + and Nb5 + cations. The calculated potential barriers for long-range proton migration pathways along the a axis and in the bc plane are 0.47 eV and 0.61 eV, respectively. This means the anisotropic proton conductivity of La3NbO7 reflects the selective preference of protons to non-shared oxide ions in the crystal.