Electronic Transport properties of ultra-thin BiFeO$_{3}$

We have investigated the electronic transport properties of rhombohedral (R) and the nearly-tetragonal (T) phase of BiFeO$_{3}$ using beyond density functional techniques, and combined with nanoscale I-V transport measurements. Using Quasi-particle GW approximation, we show the R and T phase to have significantly different electronic structures. We find that the T phase has significantly lower effective mass at the conduction band edge compared to the R phase leading to a lower effective barrier height for tunnel electrons (0.38 eV vs 3.6 eV). We therefore anticipate that tunnel devices with T phase BFO to have significantly lower resistances. Local transport measurements performed on ultra-thin BFO R phase are consistent with this inference. Tunneling measurements on the tetragonal phase films are also presented.