Effect of light-induced drop in electrical resistance of bulk SrTiO3 crystals

This paper reports on the results of the experimental investigation of the light-induced drop in electrical resistance of undoped SrTiO3 crystals exposed to illumination for a time of 10(3)-10(4) s. The revealed effect reaches five orders of magnitude and has been observed even in samples irradiated with a weakly absorbed light that is not capable of inducing interband transitions in strontium titanate. The nature of the revealed phenomenon has been explained within the framework of modern concepts, according to which in SrTiO3 crystals there is a three-dimensional network of metallized nanowires formed by extended defects, for example, edge and screw dislocations.