Full text loading...
The superlattices of 1 layer ATiO3 (A = Ca, Sr, Ba) and 1 layer SnTiO3 (SNO). (a) 1 × 1 × 2 P4mm phase perovskite SNO/ATO; (b) 1 × 1 × 2 Cm phase perovskite SNO/ATO; (c) 2 × 3 × 2 ilmenite SNO and perovskite ATO, the interface configuration is SNO(11–20)/ATO(001) according to the experimental results from Ref. 9 . The gray, green, blue and red balls are Sn, A-cations, Ti and O, respectively. The arrows indicate the polarization directions. Due to the phase transition induced by the external strain, there are two perovskite phase: P4mm and Cm, which will be discussed in detail below.
Polarization of ATO/SNO (A = Ca, Sr, Ba) as a function of the in-plane lattice constant. Solid dots are tetragonal phase (P4mm) and open dots are monoclinic phase (Cm), respectively. The polarization directions are shown in Fig. 1 . The equilibrium lattice constants are 3.85 Å for CTO/SNO, 3.90 Å for STO/SNO and 3.95 Å for BTO/SNO, respectively.
(a) The polarization direction in the monoclinic (Cm) phase as a function of the in-plane lattice constant. θ = 0°or 90° means that the polarization is along  or , respectively. (b) The polarization rotation path. The yellow solid arrow indicates the polarization direction in the Cm phase. The shadowed area (blue) is the (−110) plane.
Spontaneous polarizations of perovskite P4mm phase (ATO) n /(SNO) n as a function of the layer thickness, i.e., the interfaces separation distance.
Interfacial binding energies for the SLs. The values for ATO/P-SNO (both P4mm and Cm) are all much lower that those for ATO/I-SNO (R-3c). The unit is eV/formula unit.
Article metrics loading...