Reversible tuning of a series of intergrowth phases of the Ruddlesden-Popper type SrO(SrTiO3)n in an (001) SrTiO3 single-crystalline plate by an external electric field and its potential use for adaptive X-ray optics

Reversible structural changes of near-electrode regions of an (001) SrTiO3 (STO) single-crystal plate with perovskite-type of structure in an external electric field are described as the tunable and reversible formation of a significant volume of domains containing Ruddlesden-Popper (RP) phases of composition SrO(SrTiO3)(n) with variable n. Compositional changes are discussed to be caused by electromigration of ion complexes in the static electric field, i.e., by solid state electrolysis of the perovskite STO. Electromigration is initiated by the electric field which then stabilizes the RP domains formed. The RP domains can be described as coherently intergrown with the surrounding perovskite matrix. The X-ray scattering behaviour of these intergrowths, compared with the perovskite STO, suggests the technical use of the phenomenon for adaptive X-ray optics.