Polarons formation in Bi-deficient BaBiO${}_3$

Abstract

BaBiO${}_3$ is a charged ordered Peierls-like perovskite well known for its superconducting properties upon K or Pb doping. We present a study on the transport and electronic properties of BaBiO${}_3$ perovskite with strong Bi-deficiency. We show that it is possible to synthesize BaBiO${}_3$ thin layers with Bi-vacancies above 8-10% by depositing an yttrium-stabilized zirconia capping layer. By combining transport measurements with ab initio calculations we propose an scenario where the Bi-vacancies give rise to the formation of polarons and suggest that the electrical transport is dominated by the migration of these polarons trapped at Bi${}^{3+}$ sites. Our work shows that cation vacancies engineering -- hardly explored to date -- appears as a promising pathway to tune the electronic and functional properties of perovskites.