Introduction
In transitional metal oxides, the strong correlation between
lattice, charge, orbital, and spin leads to many novel properties. At
their interfaces, even richer physics bring about emerging properties.
Technical advances in the atomic-scale synthesis of oxide
heterostructures make it possible for these interfaces to be artifi-
cially designed [1–3]. In perovskite oxide heterostructures where
the oxygen octahedra share their vertices, the interplay among
different distortion of octahedral units can dictate many novel
functional properties [4]. One kind of interfaces between ferroelectric
and other materials, of which the electronic properties are
to be controlled, is very interesting because of the bi-stable
property, with which two states can be reached by reversing the
ferroelectric polarization with an electric field, with both changes
from structure and from electric polarization involved. The controlling
of the electronic structure can be through either the
change of electric boundary condition [5], or structural distortion
[6]. In this paper, we propose a strategy to control the electronic
bandwidths and to achieve a metal–insulator transition in a
material by stacking it onto a ferroelectric layer resulting in a
modulation of structural distortion.