Details

Autor(en) / Beteiligte

• Szot, Krzysztof
• Bihlmayer, Gustav
• Speier, Wolfgang

Titel

Nature of the Resistive Switching Phenomena in TiO2 and SrTiO3

Ist Teil von

• Solid State Physics, 2014, Vol.65, p.353-559

Ort / Verlag

Elsevier Science & Technology

Erscheinungsjahr

2014

Link zum Volltext

Beschreibungen/Notizen

• The review is devoted to the elucidation of the nature of the resistive switching (RS) phenomena in prototypical band-insulating transition metal oxides, single crystals of TiO2 and SrTiO3. Our analysis focuses on the related insulator–metal transition under the influence of different stimuli, such as chemical gradient, electrical gradient, or combination of these. We have collected evidence, including new fundamental experiments, that this reversible insulator–metal transition is a highly local process on the nanometer scale. Important factors are: (1) the mass and charge transport along dislocations, (2) the special role of the surface region with a network of dislocations, and (3) the reversible transformation of Ti-rich oxides with the general form TinO2n−1. It is demonstrated that the current flow in stoichiometric single crystals of TiO2 and SrTiO3 is channeled along the network of dislocations and that the insulator–metal transition occurs predominantly in the skin region of the crystals in connection with a heterogeneous chemical restructuring. We show that the filamentary transport through the crystals and chemical restructuring at the oxide/metal interface also lies at the heart of the electrodegradation and RS. The concept that the real crystals of TiO2 and SrTiO3 should be regarded as composite materials, consisting of a perfect dielectric matrix acting as a spectator and extended defects constituting active nanowires, leads to a paradigm change in the interpretation of the nature of the electric transport phenomena for these materials and allows to disentangle the very complex effects giving rise to RS.