Controlling transport properties at LaFeO3/SrTiO3interfaces by defect engineering.

The formation of conductive LaFeO3/SrTiO3interfaces is first time reported by pulsed laser deposition via controlling the defects of SrTiO3, which are closely related to the surface of substrate. It is found that the interfaces grown on SrTiO3substrates without terraces exhibit the two dimensional electron gas. Moreover, the conductive interfaces show a resistance upturn at low temperatures which is strongly diminished by light irradiation. These interfaces favor the persistent photoconductivity, and the enormous value of relative change in resistance, about 60 185.8%, is also obtained at 20 K. The experimental results provide fundamental insights into controlling the defects at conductive interfaces of oxides and paving a way for complex-oxides based optoelectronic devices.