First principles hybrid functional study of small polarons in doped SrCeO3 perovskite: towards computation design of materials with tailored polaron

SrCeO 3 perovskites are promising materials for hydrogen separation membranes. High hydrogen flux in SrCeO 3 is achieved by various elemental doping to increase protonic and electronic conductivity. While the effect of B-site dopants on protonic conductivity is established, the polaronic mechanism induced by B-site cations, which is essential for electronic transport, has been less understood. Using first principles hybrid functional calculations, we investigated the polaron formation and migration in SrCeO 3 perovskites doped with different elements. Our computation results revealed distinctive behaviors of different dopant elements in localizing polarons and explained previous literature results of doping SrCeO 3 for increasing electronic conductivity and hydrogen flux. In addition, new promising dopants are predicted to increase electronic conductivity. The computation approach demonstrated in this study provides a general scheme to design materials with tailored polaron formation and enhanced functional properties.