“…If the occurrence of a highly conductive region at the interface depends on the polarization of the ferroelectric oxide part, switching the direction of this polarization would allow for commanding the conductive properties of the material. Previously, the transition to the state with 2DEG at the interface, which is connected to a sharp change in the perpendicular component of the polarization at the interface, was demonstrated [ 22 , 23 , 24 ], and we detected the presence of a highly conductive state at the interface of a heterostructure based on a ferroelectric and a dielectric, Ba 0.8 Sr 0.2 TiO 3 /LaMnO 3 [ 22 ]. While optical, photoconductive, and other properties of rare earth oxides are well known [ 1 , 2 , 3 , 4 ], the optical and especially the photoconductive properties of the 2DEG on the interfaces of two insulating materials are not reported.…”