Figure 4: The strain-resurrected head-to-head FE-like polarizations and the 2DEG-hole juxtaposition in conductive LAO/STO. | Nature Communications

Figure 4: The strain-resurrected head-to-head FE-like polarizations and the 2DEG-hole juxtaposition in conductive LAO/STO.

From: Hidden lattice instabilities as origin of the conductive interface between insulating LaAlO3 and SrTiO3

Figure 4

(a) The formation of head-to-head polarizations, PLAO and PSTO in b, across the metallic LAO/STO interfaces, while null polarization for the insulating 3-uc counterpart. Positive sign points to the LAO surface. (b) The field associated with the juxtaposed 2DEG-hole, E2DEG, in the 10-uc exemplification along with the respective depolarization fields, ELAO and ESTO, of PLAO and PSTO. The diverging potentials corresponding to ELAO and ESTO drive the 2DEG formation, and the complementary holes are localized. Scheme, the geometry of PLAO, PSTO, and E2DEG with the atomistic structure of the contributing LAO and STO uc (top) derived from Fig. 2a,b, and the artwork colour coding following the associated cation intermixing in Fig. 1c. The 2DEG in STO perfectly screens ESTO. The anti-parallel E2DEG to ELAO is nonetheless like poling PLAO, with the accompanied ELAO suggesting a FE-like origin for the observed field in the LAO (Fig. 1g; refs 14, 18).

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