  By means of ab initio calculations the possibilities of switchable
spin-polarized two-dimensional electron gas (2DEG) at the interface of
antiferromagnetic and ferroelectric perovskites, i.e., LaMnO3/BaTiO3
superlattice, were investigated. We demonstrate that at the heterostructure
with TiO2/LaO interfacial layers the two-dimensional conducting state arises
mainly localized within the interfacial MnO layer. The density of states at the
Fermi-level can be tuned by ferroelectric polarization reversal. The conducting
state coexists with magnetic one mainly arose from Mn atoms.
