(329a) Proton Diffusion On KTaO3 Under Vacancies

Proton conducting perovskites work as an electrolyte, the center of a fuel cell. As an initial example, we performed DFT calculations for KTaO3 (KTO). We studied the proton transfer and rotation mechanism in defect free KTO. We also studied the native point defects, and proton transfer mechanisms near oxygen vacancies with 2+ net charge. In this work we present first-principles calculations of proton migration in KTO using the VASP code. The transition path of the proton is determined by performing the nudged elastic band (NEB) calculations. Proton diffuses in KTO involving oxygen vacancies with 2+ net charge with a barrier of 0.15 eV. These oxygen vacancies function as an anti-trap in KTO. However, little is currently known about the detailed mechanisms of proton transport in these materials, so it will be worthwhile to elucidate the rate limiting process in detail for these materials.