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The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel γ-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1015 cm−2. Herein, we report on the patterning of 2DEG at the γ-Al2O3/SrTiO3 interface grown at 650 °C by pulsed laser deposition using a hard mask of LaMnO3. The patterned 2DEG exhibits a critical thickness of 2 unit cells of γ-Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3 × 1013 cm−2, much lower than that of the unpatterned sample (∼1015 cm−2). Remarkably, a high electron mobility of approximately 3600 cm2 V−1 s−1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ∼7 × 1012 cm−2, which exhibits clear Shubnikov-de Haas quantum oscillations. The patterned high-mobility 2DEG at the γ-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devices.

Laboratory X-ray diffraction contrast tomography (LabDCT) has recently been developed as a powerful technique for non-destructive mapping of grain microstructures in bulk materials. As the grain reconstruction relies on segmentation of diffraction spots, it is essential to understand the physics of the diffraction process and resolve all the spot features in detail. To this aim, a flexible and standalone forward simulation model has been developed to compute the diffraction projections from polycrystalline samples with any crystal structure. The accuracy of the forward simulation model is demonstrated by good agreements in grain orientations, boundary positions and shapes between a virtual input structure and that reconstructed based on the forward simulated diffraction projections of the input structure. Further experimental verification is made by comparisons of diffraction spots between simulations and experiments for a partially recrystallized Al sample, where a satisfactory agreement is found for the spot positions, sizes and intensities. Finally, applications of this model to analyze specific spot features are presented.

Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO 3 /SrTiO 3 interface, stemming from the magnetic ordering of Ti 3+ ions with the mediation of itinerant electrons. Herein, we report a magnetic 2DEG at a La 7/8 Sr 1/8 MnO 3 -buffered LaAlO 3 /SrTiO 3 interface, which simultaneously shows electrically tunable anomalous Hall effect and high conductivity. The spin-polarized temperature for the 2DEG is promoted to 30 K while the mobility remains high. The magnetism likely results from a gradient manganese interdiffusion into SrTiO 3 . The present work demonstrates the great potential of manganite-buffered LaAlO 3 /SrTiO 3 interfaces for spintronic applications.