Table S1 Properties of SnTiO

Figure S7 Average polarization of n perovskite layers and local polarization of the rock-salt type SnO layer along (a) [100] and (b) [110] in RP phase SnO(SnTiO₃)_n. The volume ratio of rock-salt type SnO layers was also shown.

Figure S8 Local polarizations along [100] and [110] of each perovskite layer in RP phase SnO(SnTiO₃)_n. Layer 1 means the layer nearest to the interface, i.e. the rock-salt type SnO layer. n=1 and n=2 members are not shown because that in these structure every perovskite layer is equivalent.