Noise and electric field characterization of irradiated SrTiO3

SrTiO3 (STO) is a band insulator with a perovskite crystallographic structure, widely used as substrate for the deposition of other perovskite materials, for instance manganites or cuprates. STO surface becomes conductive under Ar(+) ion irradiation, exhibiting similar properties to STO/LaAlO(3) interface or bulk reduced STO. We report the transport and noise properties as function of temperature and electric field of Ar(+) irradiated STO exhibiting at its surface a high mobility electron gas. This system shows metallic properties with low charge densities allowing mobility measurements. The low frequency 1/f noise presents an unexpected linear dependence with the mobility which cannot be described by the usual Hooge model. The effect of the electric field at a given temperature on the mobility, magnetoresistance and low frequency noise is also presented.