Probing vacancy behavior across complex oxide heterointerfaces

Abstract

Real-time probes profile changes in vacancy distributions within substrate-supported oxide films induced by deposition processes.

Directional ionic transport across the oxide interface enables low-temperature epitaxy of rutile TiO2

“…As a result, the increased "effective" pO 2 by the enhanced J O 2À across the interface magnifies driving force for the formation of rutile TiO 2 with stoichiometry in heterostructure ( Supplementary Fig. 16); lack of oxidation in the deposited TiO 2-δ species during the growth is compensated by transferred oxygen ions from the VO 2 templates below 10,44 .…”

Oxygen diffusion in oxide thin films grown on SrTiO3

“…The depth of the exchange is not in favor of a passive, but of a forced oxygen exchange. One possible source is the formation of an oxygen deficient SrTiO 3−x film during growth leading to a difference in the chemical potential of oxygen between the oxygen deficient film and the fully oxygenated substrate [44]. To compensate the resulting chemical potential difference some oxygen is pulled from the substrate to recompense the oxygen deficiency of the film.…”

Nature of the surface space charge layer on undoped SrTiO3(001)

“…Complex oxide heterostructures with an ABO 3 -type perovskite structure have shown remarkable physical phenomena, which include colossal magnetoresistance (CMR), metal-insulator transition (MIT), high T c superconductivity, and twodimensional electron gas (2DEG). [1][2][3][4][5][6][7] Although the interfacial layers where different complex oxides form are mainly responsible for these exotic features, the exact functionality or working mechanism of oxides at the interface layer is yet fully understood. [1][2][3][8][9][10][11] Having ABO 3 -type perovskite structures, SrTiO 3 has suitable lattice mismatch for many overlayer oxides with ideal chemical/thermal stability from centrosymmetric cubic structures and has been a popular choice for many important heterostructures, [12][13][14][15] e.g., LaTiO 3 /SrTiO 3 for quasitwo-dimensional electron gas systems, ZrO 2 :Y 2 O 3 /SrTiO 3 for colossal ionic conductivity oxides, and CaCuO 2 /SrTiO 3 for high temperature superconductors.…”

“…[1][2][3][4][5][6][7] Although the interfacial layers where different complex oxides form are mainly responsible for these exotic features, the exact functionality or working mechanism of oxides at the interface layer is yet fully understood. [1][2][3][8][9][10][11] Having ABO 3 -type perovskite structures, SrTiO 3 has suitable lattice mismatch for many overlayer oxides with ideal chemical/thermal stability from centrosymmetric cubic structures and has been a popular choice for many important heterostructures, [12][13][14][15] e.g., LaTiO 3 /SrTiO 3 for quasitwo-dimensional electron gas systems, ZrO 2 :Y 2 O 3 /SrTiO 3 for colossal ionic conductivity oxides, and CaCuO 2 /SrTiO 3 for high temperature superconductors. 7,16,17 From the results of many previous research studies on heterostructures with SrTiO 3 , most of the interfacial properties such as inter-diffusion, symmetry breaking, charge rearrangement, and interfacial strain, are known to have critical effects on the physical/ chemical, mechanical, and electrical properties of the system.…”

“…7,16,17 From the results of many previous research studies on heterostructures with SrTiO 3 , most of the interfacial properties such as inter-diffusion, symmetry breaking, charge rearrangement, and interfacial strain, are known to have critical effects on the physical/ chemical, mechanical, and electrical properties of the system. [1][2][3]7,16,18 Consequently, the preparation and control of the interfacial layer with atomic level precision becomes critical to successful research on SrTiO 3 . [1][2][3]8,19 Among various interfacial properties listed above, the presence and roles of elemental vacancies become important to interpret the physical phenomena.…”