Strain dependence of the optical properties and band gap of transparent conducting BaSnO3 and SrSnO3

Recent work has shown that perovskite BaSnO3, when doped n-type by rare earth or Sb substitution, has potential as a transparent conducting oxide (TCO), replacement for In2O3:Sn (ITO). Here we discuss the properties of this material and the related SrSnO3, as well as strain dependence and epitaxy using first principles calculations. The compounds show remarkably strong strain tunability, but in a manner very different from well-studied perovskites such as SrTiO3. The differences are explained in terms of the s-electron nature of the conduction bands in these stannates.