Origin of the superior conductivity of perovskite Ba(Sr)SnO_3

摘要

ASnO_3 (A = Ba, Sr) are unique perovskite oxides in that they have superior electron conductivity despite their wide optical band gaps. Using first-principles band structure calculations, we show that the small electron effective masses, thus, good electron conductivity of ASnO_3 can be attributed to the large size of Sn in this system that gives the conduction band edge with antibonding Sn and Os characters. Moreover, we show that ASnO_3 can be easily doped by La with shallow La_A(+/0) donor level. Our results, therefore, explain why the perovskite BaSnO_3, SrSnO_3, and their alloys are promising candidates for transparent conducting oxides.