Based on first-principles calculations, we demonstrate the impact of the electric polarization on electron transport in ferroelectric tunnel junctions (FTJs). Using a $\mathrm{Pt}/{\mathrm{BaTiO}}_3/\mathrm{Pt}$ FTJ as a model system, we show that the polarization of the ${\mathrm{BaTiO}}_3$ barrier leads to a substantial drop in the tunneling conductance due to changes in the electronic structure driven by ferroelectric displacements. We find a sizable change in the transmission probability across the $\mathrm{Pt}/{\mathrm{BaTiO}}_3$ interface with polarization reversal, a signature of the electroresistance effect. These results reveal exciting prospects that FTJs offer as resistive switches in nanoscale electronic devices.

• Received 29 November 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.137201