  In polar oxide interfaces phenomena such as conductivity, superconductivity,
magnetism, one-dimensional conductivity and Quantum Hall states can emerge at
the polar discontinuity. Combining controllable ferroelectricity at such
interfaces can affect the superconducting properties and shed light on the
mutual effects between the polar oxide and the ferroelectric oxide. Here we
study the interface between the polar oxide LaAlO3 and the ferroelectric
Ca-doped SrTiO3 by means of electrical transport combined with local imaging of
the current flow with the use of scanning Superconducting Quantum Interference
Device (SQUID). Anomalous behavior of the interface resistivity is observed at
low temperatures. The scanning SQUID maps of the current flow suggest that this
behavior originates from an intrinsic bias induced by the polar LaAlO3 layer.
Our data imply that the intrinsic bias combined with ferroelectricity constrain
the possible structural domain tiling near the interface. We recommend the use
of this intrinsic bias as a method of controlling and tuning the initial state
of ferroelectric materials by design of the polar structure. The hysteretic
dependence of the normal and the superconducting state properties on gate
voltage can be utilized in multifaceted controllable memory devices.
